al-Zuhri ابن شهاب الزهري‎, محمد بن مسلم · The Book of the Adhan (The Call to Prayer)

"I came to the Prophet (S.A.W) and Bilal came out and called the Adhan and he started doing like this in his Adhan, turning to his right and left."

"This is a shepherd or a man who is away from his family." So they looked and so it was a shepherd.

"Whoever says, when he hears the Mu'adhdhin: 'Ashhadu an la ilaha illallah wahdahu la sharika lahu wa anna Muhammadan 'abduhu wa Rasuluhu, raditu Billahi Rabban, wa bil-Islami dinan was bi Muhammadin Rasula (I bear witness that there is none worthy of worship except Allah alone, with no partner or associate, and that Muhammad is the His slave and Messenger; I am content with Allah as my Lord, Islam as my religion and Muhammad as my Messenger),' his sins will be…