Musnad Ahmad 457:14

'Affan narrated to us, Hammam narrated to us, 'Ata' ibn al-Sa'ib narrated to us, he said: Salim al-Barrad narrated to us - and he said: He was more reliable to me than my own self - he said: Abu Mas'ud al-Badri said to us: "Shall I not pray for you the prayer of the Messenger of Allah, peace and blessings of Allah be upon him?" He said: "So he said the takbir, then he bowed, and he placed his palms upon his knees, and his fingers were separated upon his shins, and he kept his elbows away from his sides until everything of him was settled. Then he said: 'Allah hears those who praise Him,' and he stood upright until everything of him was settled. Then he said the takbir, and prostrated, and kept his elbows away from his sides until everything of him was settled. Then he raised his head, and sat upright until everything of him was settled. Then he prostrated the second time." He prayed four rak'ahs for us like this, then he said: "This is how the prayer of the Messenger of Allah, peace and blessings of Allah be upon him, was." Or he said: "This is how I saw the Messenger of Allah, peace and blessings of Allah be upon him, pray."