Sunan an-Nasa'i 1861
سنن النسائي#1861SahihIt was narrated that Safwan bin Muhriz said:"Abu Musa fell unconscious and they wept for him. He said: 'I say to you the words of disavowal that the messenger of Allah said: He is not one of us who shaves his head (as a sign of mourning), rends his garments, or raises his voice in Lamentation
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih Muslim
In-book reference: 21:44