Quran 47:24

أَفَلَا يَتَدَبَّرُونَ ٱلْقُرْءَانَ أَمْ عَلَىٰ قُلُوبٍ أَقْفَالُهَآ

Then do they not reflect upon the Qur'an, or are there locks upon [their] hearts?

Translation · Saheeh International