Sahih Muslim

Sahih Muslim, Hadith 1301d

Book 15: The Book of Pilgrimage
Chapter 55: Chapter: Shaving the head is preferrable to cutting the hair, although cutting the hair is permissible

باب تَفْضِيلِ الْحَلْقِ عَلَى التَّقْصِيرِ وَجَوَازِ التَّقْصِيرِ ‏‏

وَحَدَّثَنَاهُ ابْنُ الْمُثَنَّى، حَدَّثَنَا عَبْدُ الْوَهَّابِ، حَدَّثَنَا عُبَيْدُ اللَّهِ، بِهَذَا الإِسْنَادِ وَقَالَ فِي الْحَدِيثِ فَلَمَّا كَانَتِ الرَّابِعَةُ قَالَ ‏"‏ وَالْمُقَصِّرِينَ ‏"‏ ‏.‏

Ubaidullah reported this hadith with the same chain of transmitters and (it is said) that it was on the fourth turn that he (the Holy Prophet) said:

(May Allah have mercy upon) those who got their hair clipped."

Read it in place: 15. The Book of Pilgrimage