Virtues of the Qur'an

Bukhari :: Book 6 :: Volume 61 :: Hadith 582

Narrated Abdullah:

That he heard a man reciting a Quranic Verse which he had heard the Prophet reciting in a different way. So he took that man to the Prophet (and told him the story). The Prophet said, "Both of you are reciting in a correct way, so carry on reciting." The Prophet further added, "The nations which were before you were destroyed (by Allah) because they differed."