Back 
Surah 18. Al-Kahf
Ayah 57
٥٧. وَمَنْ أَظْلَمُ مِمَّن ذُكِّرَ بِـَٔايَـٰتِ رَبِّهِۦ فَأَعْرَضَ عَنْهَا وَنَسِىَ مَا قَدَّمَتْ يَدَاهُ ۚ إِنَّا جَعَلْنَا عَلَىٰ قُلُوبِهِمْ أَكِنَّةً أَن يَفْقَهُوهُ وَفِىٓ ءَاذَانِهِمْ وَقْرًا ۖ وَإِن تَدْعُهُمْ إِلَى ٱلْهُدَىٰ فَلَن يَهْتَدُوٓا۟ إِذًا أَبَدًا
[57] Now, who can be more unjust than the person before whom his Lord's Revelations are recited to admonish him, and he turns away from them and forgets the evil end to which he has paved the way with his own hands? As regards those people, who have adopted such an attitude, We have put coverings over their hearts which do not let them listen to the Qur'an, and We have produced heaviness in their ears. While in this state, they will never be guided aright howsoever you may invite them to the Guidance.54
54Allah puts a covering over the heart of a person and makes his ears hard of hearing the Truth when he adopts the attitude of contention, dispute, wrangling and argumentation towards the admonition of a well-wisher and tries to defeat the truth with the weapons of falsehood and cunning. Naturally this attitude produces in him obduracy and obstinacy so that he turns a deaf ear towards guidance, and is unwilling to realize his error before seeing his evil end. For such people pay no heed to admonition and warning and insist on falling into the abyss of perdition: then and then alone they are convinced that it was perdition towards which they were rushing headlong.