Sayyiduna Anas (may Allah be pleased with him) narrates this statement of the Noble Prophet (peace and blessings of Allah be upon him): "When a morsel of food falls from someone's hand, he should remove the dirt from it and eat it. He should not leave it for Satan, and you should wipe your bowl clean, for you do not know in which part of your food the blessing lies."
Hadith Referenceصحیح ابن حبان / كتاب الأطعمة / 5249
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرط مسلم