Allah has sealed up their hearts and hearing and over their eyes is a blindfold. They will have a terrible punishment. (Qur'an, chapter 2 verse 7)
Because of the fact that they broke their covenant, and rejected Allah's Signs, and killed the Prophets without any right to do so and said, 'Our hearts are uncircumcised,' Allah has stamped them with disbelief, so they do not believe except for very few. (Chapter 4 verse155)
Those are the people whose hearts, hearing and sight Allah has sealed up. They are the unaware. (Chapter 16 verse 108)
We have placed covers on their hearts, preventing them from understanding it, and heaviness in their ears. When you mention your Lord alone in the Qur'an, they turn their backs and run away. (Chapter 17 verse 46)
Or do they ask, 'Has he invented a lie about Allah?' If Allah willed, He could seal up your heart. By His Words Allah wipes out the false and confirms the truth. He knows what the heart contains. (Chapter 42 verse 24)
But you will not will unless Allah wills. Allah is All-Knowing, All-Wise. (Chapter 76 verse 30)
Have you seen him who takes his whims and desires to be his god – whom Allah has misguided knowingly, sealing up his hearing and his heart and placing a blindfold over his eyes? Who then will guide him after Allah? So will you not pay heed? (Chapter 45 verse 23)