Musnad Ahmad 33:397

Zayd ibn al-Hubab narrated to us, Husayn ibn Waqid narrated to me, Abu al-Zubayr narrated to me, Jabir narrated to us, he said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "Written between the eyes of the Dajjal is: 'Kafir' (disbeliever). Every believer will read it."