Overall meaning : Allah Almighty mentions some clear proofs that this Qur’an is from Him alone: Never have you, Muhammad, read a book before this Qur’an was revealed to you, nor have you ever written one with your hand. Had you been able to read and write before your prophethood, these unbelievers would have doubted your truthfulness. Rather, this Qur’an consists of clear verses that are preserved in the hearts of the Prophet and the believers, but only those who wrong themselves through unbelief and stubbornness knowingly reject our clear proofs.
The Almighty then mentions one of the idolaters’ erroneous statements and misleading arguments and then refutes it: The Quraysh idolaters say, ‘Why have no miraculous signs been sent down to Muhammad from his Lord?’ Say to them, Muhammad, ‘Miracles are only with Allah, and I am no more than a plain warner. It is not in my power to bring you miracles.’
Is it not sufficient for them that We have revealed to you the Qur’an to be recited to them? Surely in this there is a mercy and an admonition for true believers
Say, to them, Muhammad, ‘Allah is a sufficient witness between me and you. He knows all that is in the heavens and the earth, and He will repay each one as he deserves. Those who believe in falsehood and disbelieve in Allah—who is the Truth—will surely be the losers in this life and the life to come.’