Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) narrates: The Prophet Muhammad (peace and blessings be upon him) mentioned some people who will be among his Ummah; they will emerge among some people, and their distinctive sign will be shaving their heads, and they will be the worst of people (the narrator is unsure, perhaps these are the words), they will be the worst among creation, and they will be killed by the group that is closer to the truth.