Da'ud bin Qays al-Fra'a داود بن قيس الفراء الدباغ · Foods (Kitab Al-At'imah)

If the morsel of one of you falls down, he should wipe away anything injurious on it and eat it and not leave it for the devil. And he ordered us to clean the dish, for one of you does not leave it for the devil. And he ordered us to clean the dish, for one of you does not know in what part of his food the blessing lies.