Musnad Ahmad 1013:14

Abu Hazim said: The Messenger of Allah, peace and blessings of Allah be upon him, said—Abu Damra said: I do not know it except from Sahl ibn Sa’d—he said: "My likeness and the likeness of the Hour are like these two." And he separated his two fingers, the middle one and the one next to the thumb. Then he said: "My likeness and the likeness of the Hour are like two racehorses." Then he said: "My likeness and the likeness of the Hour are like a man whom his people sent as a scout. When he feared that he would be outpaced, he signaled with his garment: 'I have come, I have come.'" Then the Messenger of Allah, peace and blessings of Allah be upon him, would say: "I am that one."