Musnad Ahmad 28:55

Waki’ narrated to us, Sufyan narrated to us, from Abu Hayyan, from Abu Zur’ah, from Abdullah ibn ‘Amr, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The sun will rise from its place of setting, and the Beast will emerge upon the people during the forenoon. Whichever of them emerges before its companion, then the other is near to it." And I do not think it is anything other than the rising of the sun from its place of setting, he says: "It is the one that is first."