Surah Muhammad, Verse 24

أَفَلَا يَتَدَبَّرُونَ ٱلۡقُرۡءَانَ أَمۡ عَلَىٰ قُلُوبٍ أَقۡفَالُهَآ٢٤

afalā yatadabbarūna l-qur'āna am ʿalā qulūbin aqfāluhā

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