Chapter 18: It is recommended to lick one's fingers and wipe the bowl, and to eat a piece of food that is dropped after removing any dirt on it. It is disliked to wipe one's hand before licking it, because of the possibility that the blessing of the food may be in that remaining part. The Sunnah is to eat with three fingers - كتاب الأشربة
وَحَدَّثَنِي مُحَمَّدُ بْنُ حَاتِمٍ، وَأَبُو بَكْرِ بْنُ نَافِعٍ الْعَبْدِيُّ قَالاَ حَدَّثَنَا بَهْزٌ، حَدَّثَنَا حَمَّادُ، بْنُ سَلَمَةَ حَدَّثَنَا ثَابِتٌ، عَنْ أَنَسٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ إِذَا أَكَلَ طَعَامًا لَعِقَ أَصَابِعَهُ الثَّلاَثَ . قَالَ وَقَالَ " إِذَا سَقَطَتْ لُقْمَةُ أَحَدِكُمْ فَلْيُمِطْ عَنْهَا الأَذَى وَلْيَأْكُلْهَا وَلاَ يَدَعْهَا لِلشَّيْطَانِ " . وَأَمَرَنَا أَنْ نَسْلُتَ الْقَصْعَةَ قَالَ " فَإِنَّكُمْ لاَ تَدْرُونَ فِي أَىِّ طَعَامِكُمُ الْبَرَكَةُ " .
Anas reported that when Allah's Messenger (ﷺ) ate food he licked his three fingers, and he said:
When any one of you drops a mouthful he should remove anything filthy from it and then eat it, and should not leave it for the Satan. He also commanded us that we should wipe the dish saying: You do not know in what portion of your food the blessing lies.