Musnad Ahmad 27:961

Abu Sa'id, the freed slave of Banu Hashim, narrated to us, 'Uqbah ibn Abi al-Sahba' narrated to us, Salim narrated to us, from 'Abdullah ibn 'Umar, who said: The Messenger of Allah (peace and blessings of Allah be upon him) prayed the dawn prayer, then he gave the salutation, then he faced the direction of the sunrise and said: "Verily, the tribulation is here; verily, the tribulation is here, from where the horn of Satan rises."