And who does more wrong than he who is reminded of the Ayat (proofs, evidences, verses, lessons, signs, revelations, etc.) of his Lord, but turns away from them forgetting what (deeds) his hands have sent forth. Truly, We have set veils over their hearts lest they should understand this (the Qur’an), and in their ears, deafness. And if you (O Muhammad) call them to guidance, even then they will never be guided.

And your Lord is Most Forgiving, Owner of Mercy. Were He to call them to account for what they have earned, then surely, He would have hastened their punishment. But they have their appointed time, beyond which they will find no escape.

And these towns (population, ‘Ad, Thamud, etc.) We destroyed when they did wrong. And We appointed a fixed time for their destruction.

purification of the soul, Qur'aan, softening the hearts