Muhammad 47:24
أَفَلَا يَتَدَبَّرُونَ ٱلْقُرْءَانَ أَمْ عَلَىٰ قُلُوبٍ أَقْفَالُهَآ
Afala yatadabbaroona alqur-anaam AAala quloobin aqfaluha
Then do they not reflect upon the Qur’ān, or are there locks upon [their] hearts?
Then, do they not give serious thought to the Qur’ān, or do they have locks on their hearts?