The Book of Pilgrimage
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
Noch nicht in deutscher Übersetzung verfügbar, daher auf Englisch.
Aus Sahih Muslim, dessen Überlieferungen die Gelehrten als authentisch annehmen.