It is narrated from Hazrat Abu Saeed Khudri that the Noble Prophet (peace and blessings be upon him) and his companions had their heads shaved on the day of Hudaybiyyah, except for Uthman and Abu Qatadah. The Messenger of Allah (peace and blessings be upon him) said: May Allah have mercy on those who shave their heads (halq). The people asked: O Messenger of Allah (peace and blessings be upon him)! And those who trim their hair? He (peace and blessings be upon him) again said: May Allah have mercy on those who shave their heads (halq). The companions asked a third time: And those who trim their hair, O Messenger of Allah (peace and blessings be upon him)! He said: May Allah have mercy on those who shave their heads (halq). The companions submitted: And those who trim their hair, O Messenger of Allah (peace and blessings be upon him)! He said: (May Allah have mercy) on those who trim their hair as well.