وَقَالُوا قُلُوبُنَا فِي أَكِنَّةٍ - (And they say, " Our hearts are [ wrapped ] in covers against that to which you invite us 41:5) Here three statements of the infidels of Quraysh are reproduced. Firstly, they said that there was a cover on their hearts against his discourse, and therefore they do not understand what he says. Secondly, that their ears are deaf to listen to his speech. Thirdly, that there are barriers between him and them. The Holy Qur'an has reproduced this statement of theirs in the context of denouncing it, which indicates that these statements are wrong. But at another place, Qur'an has also stated their condition to be the same. A verse of Surah An'am states:

وَجَعَلْنَا عَلَىٰ قُلُوبِهِمْ أَكِنَّةً أَن يَفْقَهُوهُ وَفِي آذَانِهِمْ وَقْرً‌ا

But We have put coverings on their hearts, so that they do not understand, and heaviness in their ears. - 6:25.

One may doubt that there is a conflict between this verse and that of Surah An'am in this respect. But the answer is that the infidels, by saying the above, meant that they were helpless and excusable, because their hearts were curtained, their ears were leaden and there were barriers between them and him. So how could they listen to him and accept what he said? This is how they proved themselves to be helpless. And when the Holy Qur'an stated their condition (in Surah An'am) to be the same, it did not consider them to be helpless, rather held them fully capable of hearing and understanding. It is when they refused even to hear, and had no intention of understanding, then as a punishment, heedlessness and ignorance were imposed upon them, but not to the degree that they were deprived of their volition; rather if they had changed their minds even then, their abilities of hearing and understanding would have been restored fully. (Bayan-ul-Qur’ an)