Musnad Ahmad 27:975

'Affan narrated to us, Shu'bah narrated to us, 'Abdullah ibn Dinar said: He informed me, he said: I heard Ibn 'Umar saying: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, Bilal calls the Adhan at night, or Ibn Umm Maktum calls the Adhan at night, so eat and drink until Ibn Umm Maktum calls the Adhan."