In the conclusion to What's Divine about Divine Law, Christine Hayes invites scholars of later Jewish, Christian, and Islamic traditions to examine the questions about revealed and natural law that she raises in her important study of Late Antique legal theology. How, she asks, did jurists and philosophers of Judaism, Christianity, and Islam after antiquity negotiate the opposition between the view that divine law is divine due to its source, and the view that divine law is divine because it reflects the structures of the “natural order”? How did later theorists of divine law balance the Greco-Roman understanding that divine law is rational, universal, unchanging, and eternal, with the biblical view that divine law can be, and sometimes is, arational particularistic, variable, and temporary? Hayes calls attention to a few well-known Jewish and Christian thinkers such as Augustine, Maimonides, and Luther, but she leaves Islamic philosophers and jurists unexplored. In this brief essay, I hope to chart some of the ways that Muslims and those in their orbit answered the question “What is Divine about Divine Law?” By highlighting a few prominent ideas taken up by writers in the Islamicate sphere of influence that speak to this problem, I further endeavor to bring together studies of Islamic thought with studies of Late Antiquity. Due to its historical continuity and thematic engagement with Jewish, Christian, and other traditions, scholars of both Islam and Late Antiquity have much to gain from exploring the ways that thinkers within the Islamic tradition tackled the dissonance between laws discerned through reason and those revealed by God.
A logical starting point would be to interrogate the notions of revealed and natural law found in the Qurʾān: does the Qurʾān seek to establish laws that accord with reason, or laws, potentially arbitrary, solely grounded in divine will? The Qurʾān’s repeated exhortations to perform “righteous deeds” (ṣāliḥāt; e.g., Q. 2:25), without further qualification, appear to indicate that (at least some elements of) the legal system envisioned in that work adhere to standards of ethics external to the corpus of revelation. On the other hand, echoing the description found in Ezekiel 20:25 of “laws that are not good,” the Qurʾān (6:146) recounts that God gave the Jews dietary laws as a punishment for their misdeeds, suggesting that (particular?) ritual laws may not necessarily attempt to fulfill ethical mandates.
The Qurʾān further charges its adherents to follow the “ḥanīf religion (dīn)” (Q. 30:30), a description that it applies to the religion of Abraham, which, it asserts, was neither Judaism nor Christianity (Q. 3:67; 16:120). The Qurʾān also seems to imply that this “religion” was “natural,” part of man’s natural disposition (fiṭra), implanted by God (Q. 30:30). If this Abrahamic religion was neither Judaism, Christianity, or Islam, as some traditional texts and many modern scholars posit, then the Qurʾān knows of a “natural” set of practices that mandates the rejection of polytheism (Q. 16:120) and practices prayer and acts of charity (Q. 98:5). The claim, widespread among Muʿtazilites and other theologians, that Abraham’s religion and “Islam” were equivalent, indicates that there is no distinction between this “natural” set of practices and Islam; the rejection of this assumption, however, would leave room to tease out the difference between “natural” practices and any requirements imposed by revelation. As A.J. Wensinck noted long ago, divergent positions on this question led to contradictory interpretations of a well-known ḥadīth, in which Muḥammad reportedly states, “every child is born in the fiṭra; it is his parents who make him a Jew or a Christian or a Magian.” Those who understood Islam to be the “natural” religion rendered fiṭra, which standard dictionaries translate as “natural disposition” or “natural constitution,” as Islam itself, while others posited that fiṭra merely denotes an Abrahamic, pre-Islamic monotheism, lost to subsequent Jews and Christians. It is not difficult to hear the echo of ancient debates about the relationship between wisdom, reason, and revealed law in this interpretive riddle.
Hayes notes that for thinkers in the Greco-Roman orbit, the evolving and variable nature of positive law constituted one of the characteristics that distinguished it from natural law. On its face, the qurʾānic idea that Muḥammad’s revelation has abrogated earlier revelations (Q. 2:106, 16:101) appears to rest on the assumption that divine law is the product of the divine will, and can thus be subject to modification, abrogation, or nullification. This assumption becomes fully articulated in the record of an exchange, possibly imagined, between the famed Muʿtazilite Ibrāhīm al-Naẓẓām (d. 835) and an otherwise unknown Jew, Yassā ibn Sāliḥ. In this dialogue, Yassā poses al-Naẓẓām the question, “When God decrees a law is it not so that He would not have done it had it not been an [expression of divine] wisdom?” After al-Naẓẓām accedes to this assumption, Yassā responds that if so, would God’s replacement of an earlier law not constitute the rejection of wisdom? Al-Naẓẓām tells his interlocutor that abrogation, naskh, is hardly as capricious as Yassā imagines; rather al-Naẓẓām posits that:
Wisdom is of two kinds: [first] wisdom as such, non-contingent, such as justice, faith, honesty and charity, which it is inconceivable that God should ever prohibit; [second] wisdom which becomes such contingent upon its very decree, such as ritual, prayer, and fasting. Now, what God decrees of these is good and His authority is good, and should He then rescind and decree something else, that is both good and [of His divine] wisdom; for wisdom in such case is obedience to God and abiding by His decree.
In this encounter, the Jew rejects the possibility that divine law could ever be altered; they are all, in a sense, the product of divine will. Al-Naẓẓām, on the other hand, hints at a touchstone of Muʿtazilite and Ashʿarite discourse: the (contested) idea that divine law should accord with wisdom that is external to the divine. In al-Naẓẓām’s view, such “natural” laws cannot be subject to abrogation, and would presumably remain stable from before Mosaic revelation through Muḥammad’s.
Nevertheless, what might be considered the loudest voice in the Islamic tradition speaks not of divine law’s accordance with natural law but of its basis solely in divine will, or voluntarism, as George Makdisi described the perspective of one of the earliest legal theorists in the Islamic tradition, Muḥammad ibn Idrīs al-Shāfiʿī (d. 820). Indeed, al-Shāfiʿī stressed voluntarism at the expense of any concordance between natural and divine law. In his classic treatment of Muslim examination of this problem, George Hourani cites the view of the eleventh-century Andalusian Ẓāhirī Ibn Ḥazm as an extreme articulation of this idea. Ibn Ḥazm explained that, accordingly, God could choose to command idol worship or other “wrongdoings,” or even impose obligations that are impossible to satisfy but nevertheless punish man for failure to fulfil them. This voluntarist perspective on Islamic law has attained such status that when the contemporary Muslim scholar Khaled Abou El Fadl read Islam as rooted in a demand for justice, defined by factors external to revelation, another scholar could repudiate this assertion as a “discredited theological argument,” rejected by “most Muslim theologians.”
Medieval Jews in the Islamic world likewise inquired about the extent to which revealed law accords with the conclusions of reason. Saʿadya Gaon’s distinction between revealed commandments (samʿīya) and commandments demanded by reason (ʿaqlīya) is well known, and clearly engages this longstanding discussion. In recent years, the full extent of pre-Maimonidean Jewish engagement with the question of the relationship between revealed law and human reason has become increasingly clear, as Ḥaggai Ben-Shammai, David Sklare, and others have shown. For example, Qaraite and Rabbanite Jews in the tenth and eleventh centuries wondered which, if any, of the Torah’s laws obligate all of humanity. Samuel ben Ḥofni Gaon appears to have reasoned that given the fact that the performance of revealed laws aid the performance of rational laws, and since certain prophetic passages speak of punishments imposed on non-Jews for their transgression of particular non-rational laws, it stands to reason that the divine obligation to fulfill at least some revealed laws devolves on non-Jews. These must, in his view, be the Noahide laws, be they seven, thirty (see Bavli Ḥullin 92a-92b), or some other number, which Samuel apparently did not limit to those laws that he considered possible to derive through human reason. While I doubt that many readers of this site will be convinced by Samuel’s kalām-informed reading of the Noahide laws, his interpretation demonstrates that he understood universal, “natural,” norms to be reinforced by laws solely based in divine will.
Allow me to add one further wrinkle to the reverberations of the themes that Hayes explores in the world after Muḥammad’s prophecy. She explains that from the Greco-Roman perspective, any law that was subject to change was, ipso facto, disqualified from the status of divine law. Hayes dedicates more than twenty pages to showing that, on the other hand, “rabbinic sources … do not deny that biblical law changed over time” (309; emphasis in the original). The Qurʾān itself references the idea that Jesus had mitigated particular laws of the Torah (Q. 3:50), but asserts that while divine mandates found in earlier Scriptures were merely temporary, the arrival of the “seal of the prophets” (Q. 33:40) forecloses the possibility of alterations to divine law. Where the inflexibility of natural law constituted an abiding feature of the hallmarks of Greco-Roman discourses about divine law (see Hayes, 66-70), these qurʾānic claims appeal to a model of divine law that is revealed, inflexible, and (at long last) permanent. Hayes’ perspective thus sheds light on the Qurʾān’s engagement with enduring questions about the nature of divine law. For their part, the geonim and their followers in North Africa adopted a similar perspective, claiming that divine law never changed, frequently even denying that the rabbis added to it. This interreligious environment led both Jews and Muslims to insist on the unchanging nature of divine law; unlike the previous example, this latter position does not appear to be the result of speculative kalām or reflection on the essential attributes of divine law, but primarily informed by polemical notions about revelation.
In short, What's Divine about Divine Law pinpoints a series of conceptions available to later thinkers who sought to navigate divergent perspectives on the nature of revealed and rational law. Some texts adopt the claims of revealed law’s alleged rationality wholeheartedly, knowingly espousing earlier models of divine law, while others seem to back into Greco-Roman conclusions about divine law only accidentally. Any successful scholarly project begins more conversations than it completes; in the case of approaches to divine law in the Islamic world, much remains to be explored.
Dr. Marc Herman holds the Rabin-Shvidler Joint Post-Doctoral Fellow in Jewish Studies at Fordham University and Columbia University.
 Both examples are identified in Joseph Lowry, Reading the Qurʾan as a Law Book (Occasional Papers of Yale Law School, 2015), 7-8.
 See, e.g., the treatments in Fred Donner, Muhammad and the Believers: At the Origins of Islam (Cambridge, MA: Harvard University Press, 2010), 71; and Andrew Rippin, “RḤMNN and the Ḥanīfs,” in Islamic Studies Presented to Charles J. Adams¸ eds. Wael B. Hallaq and Donald P. Little (Leiden: Brill, 1991), 157-60.
 A.J. Wensinck, The Muslim Creed: Its Genesis and Historical Development (New York: Barnes & Noble, 1932), 214-15.
 As suggested by David Sklare, “Responses to Islamic Polemics by Jewish Mutakallimūn in the Tenth Century,” in The Majlis: Interreligious Encounters in Medieval Islam, eds. Hava Lazarus-Yafeh et al. (Wiesbaden: Harrassowitz, 1999), 143n22.
 Translation in John Wansbrough, The Sectarian Milieu: Content and Composition of Islamic Salvation History (Oxford: Oxford University Press, 1978), 110-11.
 George Makdisi, “The Juridical Theology of Shâfiʿî: Origins and Significance of Uṣûl al-Fiqh,” Studia Islamica 59 (1984): 43.
 George F. Hourani, Reason and Tradition in Islamic Ethics (Cambridge: Cambridge University Press, 1985), 190.
 Khaled Abou El Fadl, “Islam and the Challenge of Democracy,” and Mohammad H. Fadel, “Too Far from Tradition,” in Islam and the Challenge of Democracy, eds. Joshua Cohen and Deborah Chasman (Princeton: Princeton University Press, 2004), 20-21, 82. See Anver M. Emon, Islamic Natural Law Theories (Oxford: Oxford University Press, 2010), 14-15.
 Ḥaggai Ben-Shammai, “Some Genizah Fragments on the Duty of the Nations,” in Genizah Research after Ninety Years, the Case of Judaeo-Arabic, eds. Joshua Blau and Stefan C. Reif (Cambridge: Cambridge University Press, 1992), 24-25; see also Aaron Lichtenstein, “Noahide Laws from the Genizah: The Thirty Laws of Samuel ben Hophni Gaon,” Hebrew Studies 28 (1987): 113-16; and David Sklare, Samuel ben Ḥofni Gaon and His Cultural World: Texts & Studies (Leiden: Brill, 1996), 213-14.