The Originator is He of the heavens and the earth: and when He wills a thing to be, He but says unto it, "Be" -and it is.
Al-Baqra (The Cow) Verse 117
Allah's Apostle said, "Whenever you hear the Adhan, say what the Mu'adhdhin is saying.
Sahih Bukhari: Volume 1, Book 11, Number 585