The Islamic legal principle that "custom is authoritative" (`al-'adah muhakkamah`) is used as a source of law primarily by which school?
Q1. The Islamic legal principle that "custom is authoritative" (`al-'adah muhakkamah`) is used as a source of law primarily by which school?
Answer: Hanafi and Maliki
Explanation: The Hanafi and Maliki schools most prominently apply the maxim "al-'adah muhakkamah" (custom is authoritative), using local custom ('urf) as a formal supplementary source of Islamic law.