Mu'adh ibn Jabal

Mu'adh ibn Jabal was a Companion (sahabi) of the Prophet Muhammad, a young man of the Khazraj tribe among the Ansar — the "Helpers" of Medina who supported the early Muslim community. Biographical tradition (sira) reports that he embraced Islam as a youth and was among those who took the Second Pledge of al-Aqaba, the agreement that preceded the Prophet's move to Medina. Later sources also count him among the early memorizers of the Qur'an.

He is best remembered for a reported saying praising him as the community's leading authority on the lawful (halal) and the forbidden (haram) — that is, on Islamic legal questions of everyday conduct. This is a devotional report rather than an independently documented fact. Around 10 AH (631 CE) the Prophet is said to have sent Mu'adh to Yemen as a teacher, judge, and collector of zakat (the alms-tax). A famous dialogue in which he promises to judge first by the Qur'an, then the Sunna (the Prophet's example), then his own reasoning (ijtihad) is often quoted, but its chain of transmission is graded weak (da'if) by hadith critics (and is classically noted as not soundly connected), so it cannot be treated as certain.

After the Prophet's death, tradition places Mu'adh in Syria (Bilad al-Sham), teaching law; when the commander Abu Ubayda ibn al-Jarrah died in the plague, the caliph Umar is reported to have appointed Mu'adh to succeed him as governor of the region. Mu'adh himself died in the plague of Amwas in 18 AH / 639 CE, reportedly in his thirties (age given variously as 33-38); his tomb is traditionally sited in the Jordan Valley.