Sahih Bukhari Volume 007, Book 065, Hadith Number 289.

Narrated By 'Umar bin Al Salama : Who was the son of Um Salama, the wife of the Prophet:

Once I ate a meal with Allah's Apostle and I was eating from all sides of the dish. So Allah's Apostle said to me, "Eat of the dish what is nearer to you."