Companions of the Prophet, in Islam, followers of Muhammad who had personal contact with him, however slight. In fact, any Muslim who was alive in any part of the Prophet’s lifetime and saw him may be reckoned among the Companions. The first 4 caliphs, who are the aṣḥāb held in highest esteem among Sunni Muslims, are part of a group of 10 Companions to whom Muhammad promised paradise. The muhājirūn (those who followed the Prophet from Mecca to Medina in the Hijrah), the anṣār (the Medinese believers), and the badriyyūn (those who fought at the Battle of Badr) are all considered Companions of the Prophet. There are differing accounts of who belonged to the various groups.
The Companions, being eyewitnesses, are the most important sources of Hadith, the record of Muhammad’s sayings and activities. Shiʿi Muslims, however, take a more critical approach than the Sunnis toward the reports of the ṣaḥābah, some of whom they consider responsible for the loss of the caliphate by Ahl al-Bayt (the family of the Prophet through ʿAlī and Fāṭimah).