Surah Al-Mutaffifin 83:14

كَلَّا ۖ بَلْ ۜ رَانَ عَلَىٰ قُلُوبِهِم مَّا كَانُوا۟ يَكْسِبُونَ

No! Rather, the stain has covered their hearts of that which they were earning.

Translation: Saheeh International

Tafsir

No indeed! — a deterrent and a warning against saying such things. Rather there has slayed engulfed their hearts covering them like rust that which they earned of acts of disobedience.

Excerpt from Tafsir al-Jalalayn, commentary on 83:14, via Quran.com. The reader has the full commentary and 9 more tafsirs.