Narrated Anas:

"When the Prophet ﷺ ate, he would lick his three fingers, and he said: 'If one of you drops a piece (of food) then let him remove any harm (dirt) from it and eat it, and do not leave it for Ash-Shaitan.' And he would order us to finish (clean) the dish. And he said: 'Indeed you do not know in which part of your food is the blessing.'

[Abu 'Eisa said:] This Hadith is Hasan Gharib Sahih.

حَدَّثَنَا الْحَسَنُ بْنُ عَلِيٍّ الْخَلاَّلُ، حَدَّثَنَا عَفَّانُ بْنُ مُسْلِمٍ، حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، حَدَّثَنَا ثَابِتٌ، عَنْ أَنَسٍ، أَنَّ النَّبِيَّ ﷺ كَانَ إِذَا مَا أَكَلَ طَعَامًا لَعِقَ أَصَابِعَهُ الثَّلاَثَ وَقَالَ " إِذَا مَا وَقَعَتْ لُقْمَةُ أَحَدِكُمْ فَلْيُمِطْ عَنْهَا الأَذَى وَلْيَأْكُلْهَا وَلاَ يَدَعْهَا لِلشَّيْطَانِ " . وَأَمَرَنَا أَنْ نَسْلُتَ الصَّحْفَةَ وَقَالَ " إِنَّكُمْ لاَ تَدْرُونَ فِي أَىِّ طَعَامِكُمُ الْبَرَكَةُ " .

قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ .