Musnad Abu Ya'la al-Mawsili 9:11

Abu Khaythama narrated to us, Abd al-Rahman ibn Mahdi narrated to us, from Sufyan, from Ali ibn al-Aqmar, who said: I heard Abu Juhayfah saying: The Messenger of Allah (may Allah bless him and grant him peace) said: "I do not eat while reclining."