Body of traditional social and legal custom and practice that constitutes proper observance of Islam .
Early Muslims did not concur on what constituted sunna, because of the wide variety of pre-Islamic practices among converted peoples that had to be assimilated, reconciled, or abandoned. In the 8th century the sunna of Muhammad , as preserved in eyewitness records, was codified as the Abū Abd Allāh Shāfiī . Later Muslim scholars strengthened the authority of sunna by devising a system for attesting the authenticity of various practices claimed as descending from Muhammad. See also ilm al-hadīth ; isnād ; Sharīah ; {{link=tafsir">tafsīr .