Muhammad produced teachings.
Muhammad . According to Islamic doctrine , he was God 's Messenger ( rasūl Allāh ) sent to confirm the essential teachings of monotheism preached previously by Adam , Abraham , Moses , Jesus , and other prophets . Besides the Quran , Muhammad 's teachings and practices ( sunnah ) , found in the Hadith and sira literature , are also upheld by Muslims and used as sources of Islamic law ( see Sharia ) .