Musnad Ahmad 1018:74

Abu Salamah al-Khuza'i narrated to us, Sulayman—meaning Ibn Bilal—informed us, from 'Amr ibn Yahya ibn 'Amarah, from Sa'id ibn Yasar, from a man from Juhaynah, who said: I heard the Prophet, may Allah bless him and grant him peace, saying: "Indeed, the disbeliever drinks with seven intestines, while the believer drinks with one intestine."