Musannaf Ibn Abi Shayba 37:375

Muhammad ibn Bishr narrated to us, he said: Mis'ar narrated to us, from Sa'd ibn Ibrahim, from his father, from Abu Bakrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The terror of the False Messiah (Al-Masih ad-Dajjal) will not enter Medina. It will have, on that day, seven gates; at every gate there will be two angels."