(51) باب صِفَةِ السُّجُودِ
It was narrated from 'Ubaidullah bin Abdullah bin Aqram that his father said:
"I prayed with the Messenger of Allah (ﷺ) and I used to see the whiteness of his armpits when he prostrated."
Reference: Sunan an-Nasa'i 1108
In-book reference: Book 12, Hadith 80
English translation: Vol. 2, Book 12, Hadith 1109