Musannaf Ibn Abi Shayba 3:452

Abu Bakr narrated to us, he said: Abu Mu’awiyah narrated to us, from al-A’mash, from Ibrahim, from ‘Alqamah, who said: ‘Abdullah entered upon his brother ‘Utbah to visit him, and he found him praying upon a piece of wood. So he threw it away and said: "This is something the devil has presented. Place your face upon the ground; if you are unable, then gesture with a gesture."