Sunan Abu Dawood, Chapter: Prayer (Kitab Al-Salat)

A woman from Banu an-Najjar: Urwah ibn az-Zubayr reported on the authority of a woman from Banu an-Najjar. She said: My house was the loftiest of all the houses around the mosque (of the Prophet at Medina). Bilal used to make a call to the morning prayer from it. He would come there before the break of dawn and wait for it. When he saw it, he would yawn and say: O Allah, I praise you and seek Your assistance for the Quraysh so that they might establish Thine religion. He then would make the call to prayer. She (the narrator) said: By Allah, I do not know whether he ever left saying these words on any night.