Musnad Ahmad 962:72

Waki’ narrated to us, Hammad ibn Salamah narrated to us, from Abu Ghalib, from Abu Umamah, that he saw heads set up on the steps of the mosque of Damascus. Abu Umamah said: "Dogs of the Fire, dogs of the Fire, dogs of the Fire," three times. "The worst of the slain under the canopy of the sky. The best of the slain are those whom they killed." Then he recited: "On the Day when some faces will become white and some faces will become black" [Al-Imran: 106]. I said to Abu Umamah: "Did you hear it from the Messenger of Allah, peace and blessings of Allah be upon him?" He said: "If I had not heard it except two, or three, or four, or five, or six, or seven times, I would not have narrated it to you."