Musnad Ahmad 627:28

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from Abu Ishaq, from 'Abdullah ibn Ma'qil, from 'Adi ibn Hatim al-Ta'i, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Fear the Fire, even if it be with half a date."