كتاب صفة النبى صلى الله عليه وسلم
49  
The Description of the Prophet, may Allah Bless Him and Grant Him Peace

Yahya related to me from Malik from Abu Nuaym that Wahb ibn Kaysan said, "The Messenger of Allah, may Allah bless him and grant him peace, was brought food while his stepson Umar ibn Salama was with him. The Messenger of Allah, may Allah bless him and grant him peace, said to him, 'Say "Bismillah," and eat what is in front of you.' "

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ أَبِي نُعَيْمٍ، وَهْبِ بْنِ كَيْسَانَ قَالَ أُتِيَ رَسُولُ اللَّهِ صلى الله عليه وسلم بِطَعَامٍ وَمَعَهُ رَبِيبُهُ عُمَرُ بْنُ أَبِي سَلَمَةَ فَقَالَ لَهُ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ سَمِّ اللَّهَ وَكُلْ مِمَّا يَلِيكَ ‏"‏ ‏.‏
USC-MSA web (English) reference : Book 49, Hadith 32
Arabic reference : Book 49, Hadith 1706