Abdullah bin Zayd · The Book on Salat (Prayer)

"When we awoke, we went to Allah's Messenger to inform him of the dream. He said: 'Indeed this dream is true. So go to Bilal, for he has a better and louder voice than you. Convey to him what was said to you, so that he may call (to the prayer) with that.'" He said: "When Umar bin Al-Khattab heard Bilal calling for the prayer he went to Allah's Messenger, and he was dragging his Izar, (as he was hurrying)…