Later scholars accepted their testimony of the words and deeds of Muhammad, the occasions on which the Quran was revealed and other various important matters of Islamic history and practice. The testimony of the companions, as it was passed down through trusted chains of narrators (isnads), was the basis of the developing Islamic tradition. From the traditions (hadith) of the life of Muhammad and his companions are drawn the Muslim way of life (sunnah), the code of conduct (sharia) it requires, and the jurisprudence (fiqh) by which Muslim communities should be regulated.