Musnad Abu Ya'la al-Mawsili 94:1

Abu Musa Ishaq ibn Musa al-Ansari narrated to us, Muhammad ibn Ma'n narrated to us, my grandfather Muhammad ibn Ma'n narrated to me, from his father Ma'n ibn Nadlah, that Nadlah met the Messenger of Allah (may Allah bless him and grant him peace) at Marran, and he had with him some of his milk-yielding camels. He milked for the Messenger of Allah (may Allah bless him and grant him peace) into a vessel, and the Messenger of Allah (may Allah bless him and grant him peace) drank, then he drank from the same vessel. Then he said, "O Messenger of Allah, by the One who sent you with the truth, I used to drink seven [vessels] and I would not be satisfied nor filled." The Messenger of Allah (may Allah bless him and grant him peace) said, "Indeed, the believer drinks in one intestine, and the disbeliever drinks in seven intestines."