(2) باب التَّسْمِيَةِ عَلَى الطَّعَامِ وَالأَكْلِ بِالْيَمِينِ
Narrated `Umar bin Abi Salama:
I was a boy under the care of Allah's Messenger (ﷺ) and my hand used to go around the dish while I was eating. So Allah's Messenger (ﷺ) said to me, 'O boy! Mention the Name of Allah and eat with your right hand, and eat of the dish what is nearer to you." Since then I have applied those instructions when eating.
Reference: Sahih al-Bukhari 5376
In-book reference: Book 70, Hadith 4
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 7, Book 65, Hadith 288