Surah Ar-Rum 30:59

كَذَٰلِكَ يَطْبَعُ ٱللَّهُ عَلَىٰ قُلُوبِ ٱلَّذِينَ لَا يَعْلَمُونَ

Thus does Allāh seal the hearts of those who do not know.

Translation: Saheeh International

Tafsir

Thus does God seal the hearts of those who do not know anything of God’s Oneness in the same way that He has sealed the hearts of these aforementioned individuals.

Excerpt from Tafsir al-Jalalayn, commentary on 30:59, via Quran.com. The reader has the full commentary and 9 more tafsirs.