6:25Among them are those who listen to you; but We place covers over their hearts, to prevent them from understanding it, and heaviness in their ears. Even if they see every sign, they will not believe in it. Until, when they come to you, to argue with you, those who disbelieve will say, “These are nothing but myths of the ancients.”

6:43If only, when Our calamity came upon them, they humbled themselves. But their hearts hardened, and Satan made their deeds appear good to them.

6:46Say, “Have you considered? If God took away your hearing and your sight, and set a seal on your hearts, what god other than God would restore them to you?” Note how We explain the revelations in various ways, yet they still turn away.

6:110And We turn away their hearts and their visions, as they refused to believe in it the first time, and We leave them blundering in their rebellion.

6:113So that the hearts of those who do not believe in the Hereafter may incline to it, and be content with it, and that they may perpetrate whatever they perpetrate.

6:125Whomever God desires to guide, He spreads open his heart to Islam; and whomever He desires to misguide, He makes his heart narrow, constricted, as though he were climbing up the sky. God thus lays defilement upon those who do not believe.