Surah 32. As-Sajdah, Ayah 22

The worst and most hardened sinner is the man to whom Allah's Signs are actually brought home and who yet prefers Evil and turns away from the Light of Allah. The Signs may be in the words and guidance of a great Teacher or in some minor sorrow or warning, which he disregards with contumely. Or it may be in a catastrophic blow to his conscience, which should open his eyes, but from which he deliberately refuses to profit. The penalty-the Nemesis-must necessarily come eventually.