Musnad Abu Ya'la al-Mawsili 115:305

Ubayd Allah narrated to us, Harmy narrated to me, Shu'bah narrated to us, from Qatadah, from Anas ibn Malik, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "I and the Hour have been sent like these two," pointing with his index and middle fingers.