It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "O Allah, forgive those who shave their heads." A man said: And those who shorten their hair too. He (peace and blessings be upon him) said again: "O Allah, forgive those who shave their heads." The man said again: And those who shorten their hair too. Then on the third or fourth time he (peace and blessings be upon him) said: "And those who shorten their hair too."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12097