Musnad Ahmad 8:139

Yazid narrated to us, Muhammad ibn Ishaq informed us, from Dawud ibn Amir ibn Sa'd ibn Malik, from his father, from his grandfather, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "I shall describe the Dajjal to you with a description that no one before me has described: He is one-eyed, and Allah, the Almighty and Majestic, is not one-eyed."