Mukhtasar Muslim (Abridged) 1304 — If a morsel falls, clean it and eat

Jabir (may Allah be pleased with him) reports: I heard the Messenger of Allah (peace and blessings be upon him) say, "Satan is present with each one of you at every action he does, even when he is eating. If any of you drops a morsel, he should clean off any dirt and eat it, and not leave it for Satan. When he finishes eating, he should lick his fingers, for he does not know in which part of the food the blessing lies."