Sahih Bukhari
Food, Meals
Volume: 007 / Book Number: 065 / Hadith Number: 305
Narrated Nafi':
Ibn 'Umar never used to take his meal unless a poor man was called to eat with him. One day I brought a poor man to eat with him, the man ate too much, whereupon Ibn 'Umar said, "O Nafi'! Don't let this man enter my house, for I heard the Prophet saying, "A believer eats in one intestine (is satisfied with a little food), and a kafir (unbeliever) eats in seven intestines (eats much food)."