Ibn Umar would not eat until a poor person was brought to eat with him. One day I brought in a man who ate a great deal, and Ibn Umar said, "Nafi, do not bring this man to me again. I heard the Prophet ﷺ say, 'The believer eats with one stomach, and the disbeliever eats with seven stomachs.'"
كان ابن عمر، لا يأكل حتى يؤتى بمسكين يأكل معه، فأدخلت رجلا يأكل معه فأكل كثيرا، فقال: يا نافع، لا تدخل هذا علي، سمعت النبي ﷺ يقول: المؤمن يأكل في معى واحد، والكافر يأكل في سبعة أمعاء.
Bukhari related it in the Book of Foods (5393), and Muslim in the Book of Drinks (2060:183), both of them through Shubah, from Waqid bin Muhammad bin Zayd, from Nafi, who said, and then he narrated it.