حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا يَزِيدُ بْنُ هَارُونَ، عَنِ هِشَامٍ الدَّسْتَوَائِيِّ، عَنْ بُدَيْلِ بْنِ مَيْسَرَةَ، عَنْ عَبْدِ اللَّهِ بْنِ عُبَيْدِ بْنِ عُمَيْرٍ، عَنْ عَائِشَةَ، قَالَتْ كَانَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ يَأْكُلُ طَعَامًا فِي سِتَّةِ نَفَرٍ مِنْ أَصْحَابِهِ فَجَاءَ أَعْرَابِيٌّ فَأَكَلَهُ بِلُقْمَتَيْنِ فَقَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ ‏"‏ أَمَا أَنَّهُ لَوْ كَانَ قَالَ بِسْمِ اللَّهِ لَكَفَاكُمْ فَإِذَا أَكَلَ أَحَدُكُمْ طَعَامًا فَلْيَقُلْ بِسْمِ اللَّهِ فَإِنْ نَسِيَ أَنْ يَقُولَ بِسْمِ اللَّهِ فِي أَوَّلِهِ فَلْيَقُلْ بِسْمِ اللَّهِ فِي أَوَّلِهِ وَآخِرِهِ ‏"‏ ‏.‏

It wasnarrated that ‘Aishah said: “The Messenger of Allah (PBUH) waseating food with six of his Companions when a Bedouin came and ate itall in two bites. The Messenger of Allah (PBUH) said: ‘If he hadsaidBismillah, it would have sufficed you (all). When any one of youeatsfood, let him say Bismillah, and if he forgets to say Bismillahat thebeginning, let him say Bismillah fi awwalihi wa akhirih (Inthe Nameof Allah at the beginning and at the end).’” Translation Not Available

Book Ref: Sunan Ibn Majah Book 29 Hadith 3264
Web Ref:  Sunan Ibn Majah Vol 4 Book 29 Hadith 3264