أَفَلَا يَتَدَبَّرُونَ ٱلْقُرْءَانَ أَمْ عَلَىٰ قُلُوبٍ أَقْفَالُهَآ

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

— Muḥammad 47:24