Agency and Authority: Considering Free-Will in the Discursive Narrative on Caliphal Authority

by John D. Martin III

Introduction

The discourse regarding qadar in early Islamic political thought is significant with regard to caliphal authority and represents an avenue for dissent in the nascent caliphal state system. If free-will can be applied to parsing right and wrong in human actions and thought, then the responsibility for action falls to the actor, particularly in the case of unjust actions. If humans can be held thusly accountable, then those caliphs—and Imāms as well—who commit acts deemed unjust could potentially be challenged as the leaders of the umma and commanders of the faithful. This appears to have been the position of the Qadarīya, the group of late first/seventh century and early second/eighths Muslim ascetics who made a theological stand against determinism.¹ The concept that free-will has an effect on the decisions of the ruling elite ran contrary to quietist perspective of the the Murji’a, which required that the community remain patient in the face of an unjust caliph. It also possibly calls into question the later Shī‘ī doctrine regarding the impeccability of the Imām in his role as arbiter of spiritual matters.

Theological discourse (kalām) based on a treatment of human free-will (qadar) represented a sort of political theology as it pointedly questioned the theological justifications for the authoritative legitimacy of the caliph and set it against a different type of authority, namely the righteousness of God and the ability of humans to choose. This runs analog in its aims to the separatist discourse maintained by the Khawārij, whose discursive cry states that there should be no authority but God's authority for reckoning right and wrong, justice and injustice.² The essential theological key to the argument of any group which wished to hold the caliph accountable for the his actions is that of free-will, or qadar. Without free-will as a factor, there was no recourse against an unjust ruler, because his actions may just as well have been the actions of a direct deputy of God—“khalīfat Allāh”—ruling ostensibly by divine right, as the office seemed to have been construed by the Ummayads.³ The latter position falls in line with the Murji’a perspective.

The Qadarīya ceased in their political role after being heavily persecuted during the reign of Marwan II (127-132/744-750 CE), though this was not to be the end of the free-will political-theological discourse.⁴ Lambton argues that the Mu‘tazila rejected “the view of the divine fore-ordination of the actions and destinies of men as inconsistent with the absolute righteousness of God, [and] took over from the Qadarīs the view that man was the author of his acts and that the human will was free.”⁵ Lambton's argument that Mu‘tazila theology developed, at least in part, from that of the Qadarīya is also demonstrated by their shared position that the leader of the community must be deposed in the case of injustice, also reflecting the position of the Khawārij.⁶

Qadar, qudra and the Qadarīya

It is important to understand the theological context in which the Qadarī discourse would be discussed after its time had passed because it plays a significant role in how key terms are used when it was described. In any context, the word 'Qadarīya' is use in an exclusively derogatory manner, and never used in self-description.⁷ Additionally, it was used on both sides—by proponents of either free-will or predestination—to refer to the other.⁸ As discussed above, the Mu‘tazila took up several of the doctrinal cornerstones salvaged from the Qadarīya, but they would not use the term to describe themselves, opting rather to use it to describe the opposing camp of those who held with predestination.⁹ For the purposes of the present discussion, the word “Qadariīya” will be used exclusively to refer to the loosely associated group of mostly Baṣran scholars who are typically believed to derive their position on free-will whole or in part from al-Ḥasan al-Baṣrī (d. 110-728), one of the tābi‘ūn—the “successors.”¹⁰ He, and the controversy over his association with the Qadarīya, will be discussed at length below.

In addition to the Baṣrans, there were small groups of scholars and religious men in several other locations scattered around the Arabian peninsula and the Levant who were claimed to be Qadarīya, namely in Syria—having the second largest concentration, as well as a handful scattered between Mecca, Medina, Kūfa, and the Yemen.¹¹ The man credited with the politicization of the doctrine, Ghaylān al-Dimashqī (d. disputed, likely sometime between 105-25/724-43) was also a rather controversial figure whose followers, known as the Ghaylānīya, were classed by later scholars as Qadarīya.¹² Most of the information that exists about who the Qadarīya were comes from the work of later heresiographers such as Abū al-Ḥasan al-Ash‘arī (d. 324/935)—founder of the eponymous theological school—and Ibn Qutayba (d. 276/889)—disciple of Aḥmad b. Ḥanbal (d. 241/855) and writer of theology and adab, wherein they make lists of those associated with sects and movements that they found to be outside what they reckoned as orthodoxy.¹³

The term qadar was used differently to mean a variety of things from “God's will” to “ability to act” depending on the source consulted.¹⁴ by proto-Sunnī and Sunnī theologians—Ash‘arīs—to mean the will of God, not the free-will of humans—the Ash‘arīs reckoned human will as a subset of divine will, which is necessarily subject to divine will.¹⁵ Qadar, when reckoned in this way, is tantamount to predestination, or at the very least, determinism. This is possible because entities which are “not eternal, i.e., every being other than God, is an action,” rather than an agent unto themselves.¹⁶ The actors—humans—then, were believed to be extensions of action by way of capacity rather than embodying the ability to act. Frank M. Richards, in a formal logical treatise on the topic, explicates the terminology brilliantly: “the human agent's created ability to act is frequently described as the capacity to act (istiṭā‘a) and so formally distinguished from God's ability to act (qudra).”¹⁷

In predestination circles, above terminology was used thusly, which becomes confusing when turning to works in which free-will is the argued position. The Mu‘tazila presented a much more humanistic argument of agency and will, using qadar to as a reference to qudra which they then argued is not the ability of God to act, but the agency of humans. It is this definition of qadar that is pertinent to the present discussion with regard to agency and authority.

Richards argues that the Mu‘tazilī system is founded upon a “set of theses concerning ethical judgments,” which are axiomatic to their discourse:

1. “God is absolutely just: He will, under no circumstances, and indeed cannot, do what is ethically wrong. Albeit men right deserve to be punished for their wrongful acts, those who consistently do what is right and good deserve reward and praise.

2. “God has informed us through his prophets that He will, in another life, reward the righteous for their righteousness eternally and in a manner that goes far beyond what in simple justice they deserve, and will punish the unrepentant sinner […] and the unbeliever in eternal torment.”¹⁸

These are, quite succinctly, the grounds upon which the Qadarīyya objected to what they would have seen as a corrupt caliphate whose primary concern had become wealth accumulation and the consolidation of power into dynastic lines. It is clear from this distillation of the axioms of Mu‘tazila doctrine that their theological position on such things developed directly from that of their predecessors in speculative theology.

al-Ḥasan al-Baṣrī and His Letter

The letter attributed to al-Ḥasan al-Baṣrī (d. 109/728) addressing Caliph ‘Abd al-Malik (65-86/685-705) expresses a critique of the corruption present in the Umayyad caliphal system as it was being administered during his reign—as well as that of his successors—in the eighth century. The authenticity of al-Ḥasan's letter as a Qadarī doctrinal work—argued inconclusively by J. van Ess—is disputed.¹⁹ This does not, however, invalidate the significance of the discourse. Even if Wansbrough is correct in his assertion that the letter likely dated from the later eighth century, the political critique is still just as poignant, perhaps even more so.²⁰ That the Mu‘tazila associated al-Ḥasan al-Baṣrī and the letter with the Qadarīya is further significant given their emphasis that the “founders of their own school came from his circle in al-Baṣra.”²¹ Indeed the legendary founder of the Mu‘tazila school, Wāṣil al-‘Aṭā’ (d. 131/748) was reputed to have been a student of al-Ḥasan in Baṣra before leaving his cirle after a disagreement over the definition of “sinner.”²²

Given that “the practice of falsely attributing anecdotes and letters to al-Ḥasan al-Baṣrī was very common in medieval scholarship and was in no way restricted to him” it is nearly impossible to even partially establish authenticity authoritatively.²³ Nevertheless, the attribution of the letter to a figure of the stature of al-Ḥasan and indeed the various claims over his theological and political positions made by the “free-will camp” and the “predestination camp” further signify the importance of the discourse itself.²⁴ This frenzy of claims indicates that the particular thread of dissenting thought was a powerful one, even if it did not win out in the end and eventually gave way in most circles to Ash‘arī theological determinism.

Additionally, the phenomenon of later Sunnī scholars to dissociate al-Ḥasan al-Baṣrī from any association with the Qadarīya is instructive as to the dissenting nature of the discourse on free-will. Al-Shahrastani (d. 548/1153) “express[es] misgivings about the authenticity” of al-Ḥasan's seminal letter, in a possible attempt to distance him from Qadarī association.²⁵ Ibn Qutayba simply fails to mention the letter at all, something which prompted many to consider the possibility that it was a later spurious attribution.²⁶ Al-Ṭabarī (d. 310/923), the great chronicler, also fails to mention the letter as well and in one report describes al-Ḥasan being accused of being accused of being a Qadarī by the famous jurist Mālik b. Anas (d. 179/796).²⁷ (al-Ḥasan, as a member of the tabi‘ūn generation of scholars and theologians looms large in Islamic discourse. He is often quasi-hagiographically claimed by various Ṣūfī groups. His life is practically mythologized and his contribution to the speculative theological discourse—whether authentically attributed or not—must be considered in the context of its influence based on association with the name al-Ḥasan al-Baṣrī alone.²⁸ Helmut Ritter notes that “there is hardly any work of hortatory literature in which some of Ḥasan's sayings are not quoted.”²⁹

If the later proto-Sunnī and Sunnī narrative—having evolved out of the earlier narrative of the Murji’a—was constructed to distance al-Ḥasan al-Baṣrī from the discursive rhetoric associated with the Qadarīya, then it is safe to assume that theirs represents a discourse which threatened the authoritative hegemony of corrupt caliphs. The later proto-Sunnī and Sunnī discourse is therefore a response. “Official orthodoxy, as crystallized in the centuries after Ḥasan, could no well afford to have this pillar of the Muslim church associated with ideas that had come to be labeled as heterodox.”³⁰ Even in the case, as mentioned above, that the attribution of the letter to al-Ḥasan al-Baṣrī is spurious, a narrative that expresses the view “that the ruler was answerable for his actions and that in the case of unrighteousness he should be deposed or abdicate” is not one that anyone attempting to draw association with a legendary figure and one of the tabi‘ūn would wish to see associated with such a figure.³¹

Ghaylān al-Dimashqī, on the other hand, instead of being claimed seems to only be reckoned as a heretic or by later writers.³² His primary point of contention was the claim of exclusive Qurayshī right to reign as caliph. He believed that any pious Muslim, whether Arab or not, would be eligble as Imām—a term which was still often conflated with “caliph,” as the terms had yet not been defined by the fledgling ‘ulamā’. More importantly, Ghaylān believed that the caliph should be the best candidate (afḍal al-nās) according to those charged with his appointment.³³ Ghaylān is claimed variously to have been interrogated and sentenced to death over his preaching the Qadarī doctrine of free-will, though the timing is very difficult to pin down, because of attempts to dissociate prominent contemporaneous figures from Ghaylān's heresy.³⁴ It is likely, however, to have occurred toward the end of the reign of Hishām (105-125/724-743), according to al-Ṭabarī.³⁵

Caliphal Claims to Authority

If in fact al-Ḥasan al-Baṣrī's letter to ‘Abd al-Malik is not spurious—and the letter from ‘Abd al-Malik, or his deputy, al-Ḥajjāj, requesting al-Ḥasan's opinion on the matter is also authentic—then it can be viewed as an attempt on the part of the Caliph to establish the political sympathies of al-Ḥasan. The letter from ‘Abd al-Mālik could also have been legitimate request for an opinion on the matter ostensibly for the purposes of further legitimating the claims of the Umayyads to authority. The latter, however, is relatively implausible in the case that al-Ḥasan al-Baṣrī was sympathetic to the Qadarīya. It is also implausible considering that there were Qadarīya being executed for their political beliefs around the time that the letter is assumed to have been drafted.³⁶ There is also some dispute over the authenticity of the letter from ‘Abd al-Mālik due to the fact that though the letter indicates that it is in fact from ‘Abd al-Mālik, the rest of the text refers to the caliph in the third-person.

In some cases it has been thought, as mentioned above, that the letter in fact came from the viceroy of the caliph, al-Ḥajjāj, governor of Iraq; Ibn al-Muqtaḍā posited that this might be the case.³⁷ This is something that is debated in modern scholarship, but which seems of little importance overall. Even in the case that al-Ḥajjāj would have been the true author of the letter, it is likely that as a deputy of the caliph and the governor of a province, he was writing on behalf of the caliph. In this case, the qualitative effect is the same: that a letter was drafted from someone within the Umayyad state at a relatively high level who wished to receive an opinion from al-Ḥasan, a noted scholar and teacher operating in Baṣra. It seems more likely, however, that the letter was in fact written by a scribe in a style that was occasionally employed by officials to individuals in the early Islamic empire. The text of this letter seems to match the style of some of the official letters found in Egypt from the first/seventh century.³⁸

Regardless, it had been demonstrated by now that the matter of qadar is important for establishing caliphal authority. It could also be argued, from the above evidence, that it held importance for establishing a protocol for deposing a caliph in the case that he is deemed unworthy of the role or title. In a political climate like the one that existed for the early Umayyads, it would have been important to consider this, especially given that the alternatives—before the Qadarīya enter the conversation and the Mu‘tazila continue it—are violent removal from office by the Khawārij or allowing an unjust ruler to languish in his position.

Agency and Authority

As discussed in the introduction, the Umayyad caliphs' claim to authority was established in terms of rule by divine right. Crone and Hinds demonstrate sufficiently that there is extensive attestation for this conception of the caliph by the Ummayads—and even the ‘Abbasids—while there is very little attestation that the caliph could be understood to be khalīfat rasūl Allāh—deputy of the Prophet of God, Muḥammad.³⁹ This evidence should be relatively sufficient for establishing the position of the Ummayads with regard to their place in the religio-political scheme of the nascent Islamic state-structure. Rhetorically, this distinction would indicate that they believed that they ruled by direct divine authority rather than by an extension of the authority of the Prophet, based on the concept of ‘ādilat al-Ṣaḥaba—“the justice of the Companions of the Prophet.” Interestingly enough, this rhetorical position is very similar in spirit—though less direct—to that of the Imāmīs, who viewed the Imām as carrying an extension of the esoteric divine light of Muḥammad and his descendants in the line of Imāms.

Crone and Hinds argue that we can infer from this rhetorical example and the extent of its attestation in the literary historical narrative that the Umayyads changed their terminology for the leader of the umma from khalīfat rasūl Allāh to khalīfat Allāh, thus—at least by way of verbal rhetoric—establishing themselves as the deputies of God rather than the deputies of the Prophet.⁴⁰ The Ummayads appear as well to have adopted the doctrine of predestination “in an attempt to legitimize their claim that their rule was ordained by God.”⁴¹ Claims of this nature would of course be met with criticism by those who saw this to be a trespass of bounds in terms of religious authority. Al-Ḥasan al-Baṣrī appears not to have been aligning himself with any particular political faction, but responding on religious grounds to the Umayyads' claims to religious and temporal authority based on their position as deputies of God.

The caliph was not being chosen by means regarded as legitimate, but by powerful men, either dynastically or by force. Ibn Khaldūn (d. 808/1406) reflects that “they cannot be blamed because they gave preference to their own sons and brothers in that respect departing from the Sunna of the first four caliphs.”—referring to the Umayyads—“Their situation was different from that of the (four) caliphs who lived in an time when royal authority as such did not yet exist, and the restraining influence was religious.”⁴² This implies that the Umayyads were no longer restrained by religion. This is precisely the point that al-Ḥasan al-Baṣrī was attempting to make when accuses ‘Abd al-Mālik: “You (collectively) have pursued erroneous desires and grave [mortal] sins and corrupted/distorted the Word of God.”⁴³ This admonition should be taken as referring to the use of divine authority to justify excess and violence against other Muslims.

‘Abd al-Mālik inherited the seat of power from his father, Marwan (64-65/684-685) who had a very short reign. When he took the throne in Damascus, Abdullah b. Zubayr (d. 73/692) had laid claim to the caliphate in Mecca, and every province had turned against the Umayyads. ‘Abd al-Mālik bombarded Mecca in 72/691, damaging the Ka‘aba, until Ibn Zubayr's army surrendered. He then proceeded to establish himself as the authoritative ruler of the nascent empire by spending lavishly minting coins and building grand structures—such as the Dome of the Rock, all the while taxing heavily.⁴⁴ Michael Schwarz translated the following passage from al-Ḥasan's letter pertaining to these excesses and the attention that the Umayyads paid to worldly matters in general:

“Those who believe in predestination would blame predestination for any of their own shortcomings in questions of religion (fī amr dīnihim). But when it comes to secular questions (fī amr dunyāhum), they act very carefully and prudently. None of them would think of abstaining from work because his sustenance (rizq) is provided by God. None of them would think of not irrigating his field because it was predestined whether the grain was going to sprout or not, or of leaving his cattle to graze unprotected because it was pre-ordained whether they would be stolen or torn to pieces by beasts of prey. ”⁴⁵

This is clearly an indictment of the bureaucracy that must have been developing in the first/seventh century in the nascent empire. The passage continues to say that the loss of worldly things should not be grieved, but that the loss suffered from “missed acts of religious obedience” most certainly should be grieved.⁴⁶ This echoes in Ibn Khaldūn's above reflection about the lack of religious restraint exhibited by the Umayyads.

At the same time ‘Abd al-Mālik was resuming the Islamic conquests, the proto-Shī‘ī ‘Alawīs are still reeling from the martyrdom of Ḥusayn in 61/680 and their conception of imāma is developing as they approach the end of the first century AH/beginning of the eighth century CE. The seeds are being sewn for the revolts on the part of proto-‘Shī‘ī groups in the second/eighth century.⁴⁷ The state of ‘Abd al-Mālik's empire is not quiet and dissident groups are swiftly dealt with, to say the least, and the non-reactionary position of the Murji’a is understandable.⁴⁸ However, given the perceived excesses of ‘Abd al-Mālik and the caliphal court in its spending, ruthlessness, and vanity it is difficult not to judge the opposite position just as well. This holds particularly true for the coinage minted by the caliph in which he seals the establishment of his rule with the words khalīfat Allāh.⁴⁹

The caliph was not, of course, alone in his exaltation. Al-Ḥajjāj is said to have expressed the opinion “that God held His khalīfa on earth in higher regard than His rasūl,” and in another instance, “his messengers [rusulihi].”⁵⁰ Crone and Hinds argue that these distinctions indicate more than blasphemous flattery, but a real meaning. This would mean, then, that rule by divine right was almost certainly in effect. It also indicates, as Crone and Hinds argue as well, that the Prophet is not fully exalted yet and is simply a “lowercase-p” prophet still. Perhaps the last one, but a messenger only. The caliph, therefore held a very special role, being that he was the deputy of God on earth now that Muḥammad was gone.

The language in both ‘Abd al-Mālik's and al-Ḥasan's letters reflects that this may have been the case. They both begin with the formulaic greeting “fa’anī aḥmud ilayk Allāh alladhī la ilaha ilā huwwa... [Praise God, of Whom there is no other...]” This is followed, in the beginning of al-Ḥasan's letter—after imma ba‘d, by “aṣlaḥa Allāh amīr al-mu’minīn wa ja‘aluhu min awlīyā’ihu al-dīn. [God make the Commander of the Faithful prosperous and favor him among his saints/benefactors].”⁵¹ The caliph in this greeting is held in very high regard and the formulae which refer to God are very simple, with no mention of the Prophet Muḥammad or the caliph as his deputy.

In the epistle of Sālim b. Dhakwān which most likely dates to several years before the letter of al-Ḥasan, we find the same formula in the beginning of al-Ḥasan's letter.⁵² Sālim was a first/seventh century Ibāḍī. His epistle is directed against Kharijī extremism and Murji’a quietism, which places it in a similar philosophical place as the Qadarī thought coming from the same period. Interestingly enough, the epistle is primarily a discussion of the events surrounding the caliphates of ‘Uthman b. ‘Affān (23-35/644-655) and ‘Alī b. Abī Ṭālib (35-40/656-661). The formulaic similarity does very little for the present discussion except perhaps to demonstrate further that the letter of al-Ḥasan may in fact, at the very least, authentically come from the period contemporaneous with his life. What is more interesting is that Prophetic exaltation is a topos which shows up again and again in the epistle, whereas al-Ḥasan's letter only contains a few references to Muḥammad.⁵³ This may or may not have a great deal of significance. First, it could be explained by the fact that while al-Ḥasan's letter is some sort of official correspondence, it is also a letter addressed to the caliph for a specific purpose. Second, the topic of the letter is primarily speculative theology. The epistle of Sālim, on the other hand, is a longer work and there is a great deal of sīra contained therein.

It may simply demonstrate the difference in theological standpoints on the topic of prophets and caliphs. In this case, the Umayyads were serving their interests in holding the position that the caliph was on par with the the prophets. Al-Ḥasan was an ascetic and a non-Arab, and the aspect concerning prophets and caliphs would be the measure of justice in their actions. Sālim, an Ibāḍī, would have been on the fringes of power as well but would have looked to the Prophet as a figure of particularly keen justice, as well as the Rightly-Guided caliphs.

Conclusions

Narrative construction can be made to serve the interests of those constructing the narrative. This is true of history-writing and story-telling. It is also, as we have seen, true of theology. It is not surprising that the development of a early Islamic theological tradition should be paired with a set of distinct temporal, political interests. It is widely understood by now that this narrative line can be followed in other Islamic sciences, such as ḥadīth compilation and verification, jurisprudence, and history-writing. It is interesting to see this same trend present in speculative theology and as well to identify the specific theological or philosophical topoi used to identify trends in the larger historical narrative—such as free-will and predestination, in the focus of the present discussion.

In the case of qadar it is quite clear that there is a correlation between the rise of the free-will discourse in kalām and the perception on the part of learned men that the emerging state-system around them was problematic and confusing to reconcile with the still young religious system upon which its government was ostensibly based. This was the task of the Qadariīya, and the Mu‘tazila after them. They were pioneers amongst pioneers.

Notes

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———. Medieval Islamic Political Thought. Edinburgh: Edinburgh University Press, 2005.

Crone, Patricia and Martin Hinds. God's Caliph: Religious Authority in the First Centuries of Islam. Cambridge: Cambridge University Press, 1986.

Crone, Patricia and Fritz Zimmermann, eds. and trans. The Epistle of Sālim Ibn Dhakwān. Oxford: Oxford Univerty Press, 2001.

Ess, J. van. “Ḳadariyya.” Encyclopaedia of Islam, Second Edition. Edited by P. Bearman, Th. Bianquis, C.E. Bosworth, E. van Donzel and W.P. Heinrichs. Brill, 2009. http://0-www.brillonline.nl.lib.aucegypt.edu/subscriber/entry?entry=islam_COM-0409 (accessed 24 March 2009).

Frank, Richard M. “Two Islamic Views of Human Agency.” Classical Islamic Theology: The Ash‘arites. Texts and Studies on the Development and History of Kalām, 3. Dimitri Gutas, ed. Aldershot: Ashgate, 2008.

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Guillaume, Alfred. “Some Remarks on Free Will and Predestination in Islam, Together with a Translation of the Kitabu-l Qadar from the Sahih of al-Bukhari .” Journal of the Royal Asiatic Society of Great Britain and Ireland 1 (1924):43-63.

Ibn Khaldūn. The Mudaddimah: An Introduction to History. Translated and introduced by by Franz Rosenthal. Abridged and edited by N. J. Dawood. 1967. Reprint, Princeton: Princeton University Press, 2005.

Judd, Steven. “Ghaylan al-Dimashqi: The Isolation of a Heretic in Islamic Historiography,” International Journal of Middle East Studies 31, no. 2 (1999):161-184.

Lambton, Ann. State and Government in Medieval Islam: An Introduction to a Study of Islamic Political Theory: The Jurists. London Oriental Series, 36. Oxford: Oxford University Press, 1981.

Momen, Moojan. An Introduction to Shi‘i Islam. New Haven, CT: Yale University Press, 1985.

Mourad, Suleiman Ali. Early Islam Between Myth and History: al-Ḥasan al-Baṣrī (d. 110H/728CE) and the Formation of His Legacy in Classical Islamic Scholarship. Leiden: Brill, 2006.

Obermann, Julian. “Political Theology in Early Islam: Ḥasan al-Baṣrī's Treatise on Qadar.” Journal of the American Oriental Society 55, no. 2 (1935): 138-162.

Pellat, Ch. “G̲H̲aylān b. Muslim, Abū Marwān al-Dimas̲h̲ḳī al-Ḳibṭī.” Encyclopaedia of Islam, Second Edition. Edited by P. Bearman, Th. Bianquis, C.E. Bosworth, E. van Donzel and W.P. Heinrichs. Brill, 2009. http://0-www.brillonline.nl.lib.aucegypt.edu/subscriber/entry?entry=islam_SIM-2480 (accessed 16 April 2009).

Ritter, H. “Ḥasan al- Baṣrī , Abū Saʿīd b. Abi 'l-Ḥasan Yasār al-Baṣrī (21/642-110/728).” Encyclopaedia of Islam, Second Edition. Edited by P. Bearman, Th. Bianquis, C.E. Bosworth, E. van Donzel and W.P. Heinrichs. Brill, 2009. http://0-www.brillonline.nl.lib.aucegypt.edu/subscriber/entry?entry=islam_COM-0273 (accessed 21 March 2009).

———. “Studien zur Geschichte der islamischen Frömmigkeit.” Der Islam 21 (1933):1-83.

Schwarz, Michael. “The Letter of Ḥasan al-Baṣrī.” Oriens 20 (1967): 15-30.

Ṭabarī, al-, The History of al-Ṭabarī: The Waning of the Umayyad Caliphate. Translated by Carole Hillenbrand. SUNY Series in Near Eastern Studies: The History of al-Ṭabarī, 26. Albany, NY: State University of New York Press, 1989.

Takim, Likayat. The Heirs of the Prophet: Charisma and Religious Authority in Shi‘ite Islam. Albany, NY: State University of New York Press, 2006.

Wansbrough, John. Quranic Studies: Sources and Methods of Scriptural Interpretation. London Oriental Series, 31. Oxford: Oxford University Press, 1977.