Musannaf Ibn Abi Shayba 3:731

Abu Mu'awiyah and Waki' narrated to us, from al-A'mash, from 'Umarah, from al-Aswad, who said: 'Abdullah said: "Let none of you assign a portion of himself to the Shaytan, thinking that it is a duty upon him that he must perform, such that he thinks he should not turn [away from prayer] except from his right side. For I have seen the Messenger of Allah (ﷺ) turn away from his left side more often."