Surah Al-An'am 6:25
وَمِنْهُم مَّن يَسْتَمِعُ إِلَيْكَ ۖ وَجَعَلْنَا عَلَىٰ قُلُوبِهِمْ أَكِنَّةً أَن يَفْقَهُوهُ وَفِىٓ ءَاذَانِهِمْ وَقْرًا ۚ وَإِن يَرَوْا۟ كُلَّ ءَايَةٍ لَّا يُؤْمِنُوا۟ بِهَا ۚ حَتَّىٰٓ إِذَا جَآءُوكَ يُجَـٰدِلُونَكَ يَقُولُ ٱلَّذِينَ كَفَرُوٓا۟ إِنْ هَـٰذَآ إِلَّآ أَسَـٰطِيرُ ٱلْأَوَّلِينَ
And among them are those who listen to you, but We have placed over their hearts coverings, lest they understand it, and in their ears deafness. And if they should see every sign, they will not believe in it. Even when they come to you arguing with you, those who disbelieve say, "This is not but legends of the former peoples."
Translation: Saheeh International
Tafsir
And there are some of them who listen to you when you recite and We have placed veils covers upon their hearts so that they do not understand it so that they do not comprehend the Qur’ān; and in their ears a heaviness a deafness so that they do not hear it with a willingness to accept it. …
Excerpt from Tafsir al-Jalalayn, commentary on 6:25, via Quran.com. The reader has the full commentary and 9 more tafsirs.