JAʿFAR B. MOḤAMMAD B. ḤARB, ABU’L-FAŻL AL-HAMDĀNI (d. 236/850 at the age of 59), also called al-Ašajj (‘scar-face’ or ‘skull-broken’), Muʿtazilite theologian who lived in Baghdad. His family was of Yemeni descent, as is shown by the nesba (cf. Masʿudi, Moruj, ed. Pellat, V, p. 21), and the reading Hamaḏāni, which would turn him into a Persian (Nader, p. 373; Sezgin, GAS I, p. 619), has to be abandoned. The ancestral relations of Jaʿfar b. Ḥarb are difficult to reconstruct. His name is normally shortened to Jaʿfar b. Ḥarb, but Ḥarb was, in fact, the name of his grandfather or great-grandfather (cf. Tawḥidi, IV, p. 215, no. 783), who seems to have been a person of some renown and was possibly identical with an Abbasid general who died in 147/764 (Masʿudi, Moruj, ed. Pellat, V, p. 21; cf. van Ess, 1991-97, III, p. 12). His father, a certain Moḥammad b. Ḥarb, may have been the chief of police in Basra for some time, and this would, at least, best explain why, in his youth, Jaʿfar b. Ḥarb studied with Abu’l-Hoḏayl ʿAffāf (ca. 135-227/752-841; q.v.), who lived there, and not with Bešr b. al-Moʿtamer (for him see van Ess, 1991-97, III, pp. 107-30), the head of the Muʿtazilite movement in Baghdad. At a later date, the Abbasid governor Qoṯam b. Jaʿfar invited Jaʿfar b. Ḥarb to Basra again for a disputation with his former teacher, when Abu’l-Hoḏayl was already at a rather advanced age (van Ess, 1994, pp. 14 f.). For some time Jaʿfar b. Ḥarb had a position in the army, and the scar on his forehead may have been the trace of a wound, which he had got in battle. However, the Muʿtazilite tradition avoids the nickname Ašajj and rather presents him as somebody who, because of his piety, was invited to the court of the Abbasid caliph al-Wāṯeq (r. 227-32/842-47) and had discussions there with the Ibadite (Ebāżi; see Lewicki, pp. 648-60) scholar Yaḥyā b. Kāmel, the contents of which seem to have been subsequently published as al-Masāʾel al-jalila (‘The Important Questions’; see Ebn al-Nadim, ed. Tajaddod, pp. 213, 233). Both theologians are said to have been friends, which would be all the more plausible, if we can assume that Jaʿfar’s father was identical with Moḥammad b. Ḥarb, who is mentioned as an Ibadite theologian by Ašʿari (pp. 108, 120, line 7). But this suggestion, again, necessarily remains highly hypothetical (van Ess, 1991-97, IV, pp. 173 ff.). Before al-Wāṯeq came to power, however, Jaʿfar b. Ḥarb had already passed through a religious crisis which had made him renounce his military job (and perhaps his pecuniary security too). He had passed under the influence of Abu Musā Mordār (q.v.; see van Ess, 1991-97, III, pp. 134-35 and 138 f.), a Muʿtazilite with a Persian nickname (mordār means ‘carrion’), who had strong ascetic leanings and died in 226/841. Mordār called on him to do penance for his former life, and by diving into the river Tigris Jaʿfar b. Ḥarb washed off his sins; afterwards he put on new clothes offered to him by Mordār (ʿAbd-al-Jabbār, p. 278). These may have been Sufi garments, because the group of Baghdadi intellectuals, whom he joined, was named Ṣufiyat al-moʿtazela at that time (van Ess, 1991-97, III, pp. 130 ff.). The main sin, however, from which he wanted to be absolved was probably that of having worked for the government, and in the army at that.

The crisis affected Jaʿfar b. Ḥarb’s theological outlook. Trained by Abu’l-Hoḏayl, he had started as an atomist; unlike his contemporary Jāḥeẓ (q.v.), he did not feel tempted by the “naturalist” approach of Abu Esḥāq Naẓẓām (q.v.). Yet he had attacked Abu’l-Hoḏayl because of the latter’s idea that even in paradise all human actions will come to an end, and, therefore, the blessed have to remain in eternal immobility. This may have been the subject of his Ketāb towbiḵ Abi’l-Hoḏayl (van Ess, 1991-97, III, pp. 260 f.). In Baghdad, Jaʿfar b. Ḥarb had to take notice of Bešr b. al-Moʿtamer’s theory of benevolence, which purported that, since the Muʿtazilites could not uphold God’s “creating” belief or unbelief, they had to explain the difference between Muslims and pagans by an act of God’s benevolence (loṭf) being accorded to those who have the true faith (van Ess, 1991-97, III, pp. 121 f.). This, however, seemed to contradict the Muʿtazilite idea that God always acts in the most salutary (aṣlaḥ) way for everybody, that is, even for unbelievers. The geographical expansion of the Muʿtazilites had resulted in a certain incongruity of the “system,” which expressed itself in the rise of two different schools of Basra and Baghdad, and Jaʿfar b. Ḥarb may therefore have felt reduced to merely adding footnotes to insolvable problems. In any case, the sources confirm that, after his “conversion,” he did not deal with doctrinal niceties any more, but rather decided to write about broad subjects for a large audience. Mordār had taken the same step before him.

The titles of a few books which belong to this late period are quoted, via Ebn Yazdād, the early historian of the Muʿtazilite school, by Qāżi ʿAbd-al-Jabbār (p. 282): Naṣiḥat al-ʿāmma, al-Iżāḥ, al-Mostaršed, al-taʿlim, and al-Diāna. Furthermore, he lists a Ketāb al-oṣul which, however, may have pertained to a different literary genre, for it seems highly probable that, as W. Madelung has suggested (pp. 220-36), the Ketāb oṣul al-neḥal, edited under the name of a relatively well-known later Muʿtazilite al-Nāšiʾ al-Akbar, was in reality written by Jaʿfar b. Ḥarb. This book would then be, to date, the oldest specimen, at least partially preserved, of Islamic heresiography, and the fact that it is the only work where the Ṣufiyat al-moʿtazela are mentioned under this expression and are extensively treated as a separate group would be of special significance. In another treatise entitled Ketāb motašābeh al-Qorʾān, Jaʿfar b. Ḥarb seems to have commented upon the predestinarian verses of the Qurʾān; the text was still known to the Muʿtazilite Ebn al-Ḵallāl (Sezgin, GAS I, 624) when, more than one century later, he wrote his Radd ʿalā al-jabriya.

As the head of the Baghdad school, Jaʿfar b. Ḥarb was followed by Eskāfi (q.v.) who, however, survived him by a few years only. He remained a provocative figure for Shiʿite and Sunnite theologians alike. Ḥasan b. Musā Nowbaḵti (q.v. at www.iranica.com) and Mofid criticized him because of his concept of leadership (emāmat), for, in spite of having high respect for Imam ʿAli (whom he seems to have regarded as the founder of Islamic theological thinking), he did not believe in the prerogatives of the imams. He was also attacked by ʿAbd-al-ʿAziz b. Moḥammad b. Esḥāq Ṭabari, known as Dommal, a pupil of Ašʿari (Ebn ʿAsāker, XLIII, pp. 7, 16 f.), and by ʿAbd-al-Qāher Baḡdādi (q.v.) in his Ketāb al-ḥarb ʿalā Ebn Ḥarb, but we do not know for what reasons (for more details on books and refutations, see van Ess, 1991-97, VI, pp. 288-90; for doxographical material, see VI, pp. 290-300).


Qāżi ʿAbd-al-Jabbār, Fażl al-eʿtezāl, ed. Foʾād Sayyed, Tunis, 1974.

ʿAli b. Esmāʿil Ašʿari, Maqālāt al-eslāmiyin, ed. H. Ritter, 3 vols., Istanbul, 1927-33, index, s. n. Ebn ʿAsāker, Taʾrik Demašq, ed. ʿOmar b. Ḡarāma ʿAmrawi, 70 vols., Damascus 1402/1981.

J. van Ess, Theologie und Gesellschaft im 2. und 3. Jahrhundert Hidschra: eine Geschichte des religiösen Denkens im frühen Islam, 6 vols., Berlin and New York, 1991-97; IV, pp. 68-77 for Jaʿfar b. Ḥarb. Idem, “Abu l’Hudhayl in Contact: The Genesis of an Anecdote,” in Islamic Theology and Philosophy: Studies in Honor of George F. Hourani, ed. M. E. Marmura, Albany, 1984, pp. 13-30.

D. Gimaret, La doctrine d’al-Ash’ari, Paris, 1990, pp. 105, 306 f., 317.

T. Lewicki, “al-Ibāḍiyya,” in EI2 III, 1971, pp. 648-60. W. Madelung, “Frühe mu’ta-zilitische Häresiographie: das Kitāb al-Uṣūl des Ğaʿfar b. Ḥarb,” Der Islam 57, 1980, pp. 220-36.

A. N. Nader, “Djaʿfar b. Ḥarb,” in EI2 II, 1965, p. 373.

C. Schöck, Koranexegese, Grammatik und Logik, Leiden, 2006, pp. 210 f. Šahrastāni, Livre des Religions et des Sectes, tr. D. Gimaret and G. Monnot, 2 vols., Paris, 1986-93; I, pp. 218 f., 243 f. Abu Ḥayyān Tawḥidi, Al-baṣaʾer wa’l-ḏaḵāʾer, ed. W. Qāżi, 9 vols. in 5, Beirut, 1408/1988.

C. Tunç, “Ca’fer b. Harb,” Türkiye diyanet vakfı İslâm ansiklopedisi VI, 1992, pp. 549-51.

(Joseph van Ess)

Originally Published: December 15, 2008

Last Updated: April 5, 2012

This article is available in print.
Vol. XIV, Fasc. 4, pp. 347-348

Cite this entry:

Joseph van Ess, “JAʿFAR B. MOḤAMMAD B. ḤARB,” Encyclopædia Iranica, XIV/4, pp. 347-348, available online at http://www.iranicaonline.org/articles/jafar-b-mohammad-b-harb (accessed on 30 December 2012).