And Yahya ibn Yahya and Muhammad ibn Rumh narrated to us, both saying: Layth informed us. (Another chain:) And Qutaybah narrated to us, saying: Layth narrated to us, from Nafi', that 'Abdullah said: The Messenger of Allah, peace and blessings be upon him, shaved his head, and a group of his companions shaved theirs, while some of them shortened theirs. 'Abdullah said: The Messenger of Allah, peace and blessings be upon him, said: "May Allah have mercy on those who shave their heads" — once or twice — then he said: "and those who shorten their hair."