Easy Quran for Busy Folks.

And We have indeed made the
Qur'an easy to understand and
remember; then is there any that
will receive admonition?[54.17]

Let's believe the certainty of the verse.

The Messenger believeth in what hath been revealed to him from his Lord, as do the men of faith. Each one (of them) believeth in Allah, His angels, His books, and His messengers. "We make no distinction (they say) between one and another of His messengers." And they say: "We hear, and we obey: (We seek) Thy forgiveness, our Lord, and to Thee is the end of all journeys."

Sura Bakara