Musnad Ahmad

It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) was once walking on a road in Makkah until he reached a place called Jamdan. He said, "This is Jamdan, move on, and the 'Mufarridun' have gone ahead." The companions (may Allah be pleased with them) asked, "O Messenger of Allah (peace and blessings be upon him), who are the Mufarridun?" He replied, "Those who remember Allah abundantly." Then the Prophet (peace and blessings be upon him) said, "O Allah, forgive those who shave their heads." The companions (may Allah be pleased with them) submitted, "O Messenger of Allah! Pray for those who trim their hair as well." The Noble Prophet (peace and blessings be upon him) again said, "O Allah, forgive those who shave their heads." The third time, the Noble Prophet (peace and blessings be upon him) included those who trim their hair in his supplication.