The wording of Adhan

 191. Abu Madhurah narrated that the Prophet salla alayhi wa sallam taught him this Adhan: ´´Allah is the Greatest, Allah is the Greatest; I testify that there is no true God but Allah, I testfy that there is no true God but Allah, testify that Muhammad is the Messenger of Allah, I testify that Muhammad is the Messenger of Allah;´´ and it should be again repeated: ´´I testify that there is no true God but Allah, I testify that there is no true God but Allah;´´ (twice) ´´ I testify that Muhammad is the Messenger of Allah;´´ (twice) ´´Come to the prayer;´´ (twice). ´´Come to success;´´ (twice). Ishaq (i.e., bin Ibrahim) added: ´´Allah is the Greatest, Allah is the Greatest; there is no true God but Allah.´´