Musnad Ahmad 17726 — Hadith of 'Adi ibn 'Umayrah al-Kindi

It is narrated from Hazrat Adi bin Umairah (may Allah be pleased with him) that when the Prophet (peace and blessings be upon him) performed prostration, the whiteness of his blessed armpits would become visible. When he turned his face to the right while saying salam, the whiteness of his right cheek would become visible, and when he turned his face to the left, the whiteness of his left cheek would become visible. The previous hadith is also narrated through this second chain of transmission.