ذَٰلِكَ بِأَنَّهُمْ ءَامَنُوا۟ ثُمَّ كَفَرُوا۟ فَطُبِعَ عَلَىٰ قُلُوبِهِمْ فَهُمْ لَا يَفْقَهُونَ
Tha lika biannahum a manoo thumma kafaroo fa t ubiAAa AAal a quloobihim fahum l a yafqahoon a this, because [they profess that] they have attained to faith, whereas2 [inwardly] they deny the truth - and so, a seal has been set on their hearts, so that they can no longer understand [what is true and what false].3
 - Mohammad Asad
This is because they believed and then renounced their faith. Their hearts are sealed, therefore, they are devoid of understanding.
 - Muhammad Farooq-i-Azam Malik
This is because they believed and then abandoned faith. Therefore, their hearts have been sealed, so they do not comprehend.
 - Mustafa Khattab
That is because they believed, then disbelieved, therefore their hearts are sealed so that they understand not.
 - Marmaduke Pickthall
That is because they believed then they rejected Faith: so a seal was set on their hearts: therefore they understand not. 5468
 - Abdullah Yusuf Ali