Jabir (May Allah be pleased with him) reported:
Messenger of Allah (ﷺ) said, "When a morsel of any of you falls, he should pick it up and remove any of the dirt on it and then eat it, and should not leave it for Satan nor should wipe his hand with towel until he has licked his fingers, for he does not know in what portion of the food the blessing lies."[Muslim].
App reference: Book 3, Hadith 24
Arabic/English book reference: Book 3, Hadith 751