Narrated `Abdullah bin Malik bin Buhaina: Whenever the Prophet (ﷺ) used to offer prayer he used to keep arms away (from the body) so that the whiteness of his armpits was visible.
The chain is ordered from the source of the saying to the compiler: 1 = the speaker/first transmitter, the following links those who passed it on in turn, and at the bottom al-Bukhari who compiled the work. Click a narrator to list every hadith in which he appears; the number in parentheses is how many hadiths in this collection the narrator appears in.