Overall meaning : Say, Muhammad, to My servants who have transgressed against themselves by committing untold sins, ‘Do not despair of Allah’s mercy; surely Allah forgives all sins. He alone is the All-Forgiving, the All-Merciful.’
Turn in penitence to your Lord, mankind, and submit to Him before His punishment comes upon you, for then there will be none to help you and protect you against it.
Follow the Qur’an, which is the best of what Allah has revealed to His Messenger, by observing what it commands and avoiding what it forbids, before His punishment comes upon you suddenly while you are unaware, lest anyone should remorsefully say on Judgement Day, having missed the opportunity to repent, ‘Alas for me for having neglected my duty towards Allah! Indeed, I was among those who ridiculed His religion and its followers,’ or should say, ‘Had Allah guided me to the truth, I would surely have been among the God-fearing who obey His commands.’ Or should say, when he sees the punishment, ‘If only I could return once more to the world, so that I could be among those who do good.’
Allah will rebukingly expose his lies, saying: The matter is not as you say. The verses of the Qur’an did come to you, but you denied them. You were too arrogant to accept them and you were among those who disbelieved them.