Call to Prayers (Adhaan) 
Bukhari :: Book 1 :: Volume 11 :: Hadith 607
Narrated 'Aun bin Abi Juhaifa:
My father said, "I saw Bilal turning his face from side to side while pronouncing the Adhan for the prayer."
Call to Prayers (Adhaan)
Bukhari :: Book 1 :: Volume 11 :: Hadith 607
Narrated 'Aun bin Abi Juhaifa:
My father said, "I saw Bilal turning his face from side to side while pronouncing the Adhan for the prayer."