Overall meaning : This surah opens with the ‘disconnected letters’, which have already been discussed before. The Almighty then says: We have not sent down the Qur’an to you, Muhammad, to cause you distress. Rather, We have revealed it to be a reminder to those who fear Allah and His punishment.
Then, stating the source of this Qur’an, He says: This Qur’an has been sent down from Allah, who has created the earth and the lofty heavens—the All-Compassionate God, who has established Himself upon the Throne, as befits His majesty and greatness.
After that, He points out His absolute authority and complete power: To Him belongs whatever is in the heavens and whatever is on earth, and whatever lies in between them and all that lies under the ground. Whether you, Muhammad, speak loudly or quietly, know that nothing whatsoever is hidden from Allah, for He certainly knows what is secret and what is even more hidden, which has not yet entered people’s hearts and they have not thought of yet.
Next He Praises Himself as is His due: He is Allah—there is no god worthy of worship except Him. He has the Most Beautiful Names.