Sunan an-Nasa'i 1147
سنن النسائي#1147SahihIt was narrated that Maimunah said:"When the Messenger of Allah (ﷺ) prostrated, he would hold his arms out to his sides, so that the whiteness of his armpits could be seen from behind. And when he sat he rested on his left thigh
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
In-book reference: 12:119