Musnad Abu Ya'la al-Mawsili 9:6

Abu Khaythama narrated to us, Jarir narrated to us, from Mansur, from Ali ibn al-Aqmar, from Abu Juhayfa, who said: I was with the Prophet, may Allah bless him and grant him peace, and he said to a man who was with him: "I do not eat while reclining."