Musnad Ahmad 30:1503

Harun ibn Ma'ruf narrated to us, and Abdullah said: I heard it myself from Harun, he said: Abdullah ibn Wahb narrated to us, he said: Amr ibn al-Harith informed me that Bukayr ibn al-Ashajj narrated to him that Ali ibn Khalid al-Du'ali narrated to him that al-Nadr ibn Sufyan al-Du'ali narrated to him that he heard Abu Hurayrah saying: We were with the Messenger of Allah, peace and blessings of Allah be upon him, at the mountain passes of Yemen. Bilal stood up and called out [the Adhan]. When he fell silent, the Messenger of Allah, peace and blessings of Allah be upon him, said: "Whoever says the like of what this one said, with certainty, will enter Paradise."