Full Sharh — Mishkat al-Masabih 4000
وَعَن جَابر قَالَ: النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ: " إِنَّ الشَّيْطَانَ يَحْضُرُ أَحَدَكُمْ عِنْدَ كُلِّ شَيْءٍ مِنْ شَأْنِهِ حَتَّى يَحْضُرَهُ عِنْدَ طَعَامِهِ فَإِذَا سَقَطَتْ من أحدكُم لقْمَة فَلْيُمِطْ مَا كَانَ بِهَا مِنْ أَذًى ثُمَّ ليأكلها وَلَا يَدعهَا للشَّيْطَان فَإِذا فرع فليلعق أصَاب فَإِنَّهُ لَا يَدْرِي: فِي أَيِّ طَعَامِهِ يَكُونُ الْبركَة؟ ". رَوَاهُ مُسلم
English Translation
Jabir told that he heard the Prophet say, “The devil is present with one of you in everything he does, even being present when he is at food; so if any of you drops a mouthful he should wipe away anything injurious on it and eat it and not leave it for the devil; and when he finishes he should lick his fingers, for he does not know in what part of the food the blessing lies.” Muslim transmitted it.
Source
Mishkat al-Masabih(مشكاة المصابيح)
Foods
Hadith Number
4000