It is narrated from Hazrat Ka'b (may Allah be pleased with him) that during the time of Hudaybiyyah, the Noble Prophet (peace and blessings be upon him) came to me. My hair was very long. The Noble Prophet (peace and blessings be upon him) said, "Perhaps the lice on your head have troubled you a lot?" I replied, "Yes!" The Noble Prophet (peace and blessings be upon him) then ordered him to shave his head and said, "Fast for three days, or feed six needy people, each with two mudd of food, or offer a sacrifice of one goat."