Sunan Abu Dawud
891
Sahih+3

‘Abbas b. ‘Abd al-Muttalib said that he heard the Messenger of Allah (ﷺ) as saying:when a servant (of Allah) prostrates himself, the seven limbs, i.e, his face, his palms, his knees and his feet prostrate along with him

SahihAl-Albani
SahihMuhammad Muhyi Al-Din Abdul Hamid