Those who have attained to faith, and who have not obscured their faith by wrongdoing-it is they who shall be secure, since it is they who have found the right path!
Al-An'am (The Cattle) Verse 83
Allah's Apostle said, "Whenever you hear the Adhan, say what the Mu'adhdhin is saying.
Sahih Bukhari: Volume 1, Book 11, Number 585