Mukhtasar Bukhari

Narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings of Allah be upon him) said: "O Allah! Have mercy on those who shave their heads." The companions submitted, "O Messenger of Allah! (Pray for mercy) for those who trim their hair as well." The Prophet (peace and blessings of Allah be upon him) said: "O Allah! Send mercy upon those who shave their heads." The companions again submitted, "O Messenger of Allah! (Pray for mercy) for those who trim their hair as well." So the Prophet (peace and blessings of Allah be upon him, the third time) said: "And (have mercy) on those who trim their hair as well."