Islamic study of law is based on the four sources of law. The Quran is the primary source of Islamic law. The Sunnah or the life of Prophet Muhammad (Peace be upon Him) is the secondary source of Islamic law. The Quranic states, Indeed in the Messenger of Allah (Muhammad PBUH) you have a good example to follow (Quran Al Ahzab 33:21). The Ijtihad (reasoning) and Ijma (consensus of the juristic opinions) are the tertiary sources of Islamic Law.