Musnad Ahmad 33:273

Abu Mu'awiyah narrated to us, Al-A'mash narrated to us, from Abu Sufyan, from Jabir, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "If the morsel of one of you falls, let him take it, and let him remove whatever is upon it of harm, and let him eat it, and let him not leave it for the Shaytan."