He heard the Messenger of Allah (ﷺ) say: "When a person prostrates, seven parts of his body prostrate: his face, his two palms, his two knees and his two feet."
Sunan an-Nasa'i Book 12, Hadith 66
← Previous Hadith "The Prophet (ﷺ) was commanded to prostrate on seven parts of his body and not to tuck up his hair or his garment."

Sunan an-Nasa'i Book 12, Hadith 65 Next Hadith → "My two eyes saw the traces of water and mud on the forehead and nose of the Messenger of Allah (ﷺ), from his praying Qiyam on the night of the twenty-first."

Sunan an-Nasa'i Book 12, Hadith 67