Musnad Ahmad 31:922

'Affan narrated to us, Hammad ibn Salamah narrated to us, Sa'id al-Jurayri informed us, from Abu Nadrah, from Abu Sa'id al-Khudri, who said: We went on Hajj and stopped under the shade of a tree. Ibn Sa'id came and sat beside me. I said: "May Allah not pour this upon me, for he has come to me." He said: "O Abu Sa'id, do you not see what I am enduring from the people? They say: 'You are the Dajjal.' Have you not heard the Prophet, peace and blessings of Allah be upon him, say: 'The Dajjal will have no children born to him, and he will not enter Medina or Mecca'? I have just come from Medina, and I am now going to Mecca"—Hammad said: "And he had entered Mecca"—"and children have been born to me." I even felt pity for him. Then he said: "By Allah, I am the person who knows his location best right now." I said: "Woe to you for the rest of the day."