Allah has set a seal upon their hearts and upon their hearing, and over their vision is a veil. And for them is a great punishment.

خدا نے ان کے دلوں اور کانوں پر مہر لگا رکھی ہے اور ان کی آنکھوں پر پردہ (پڑا ہوا) ہے اور ان کے لیے بڑا عذاب (تیار) ہے
All actions are referred to God. Therefore when we get the penality of our deliberate sin, and our senses become impervious to good, the penality is referred to the justice of God.

The penalty here is the opposite of the prosperity referred to ayat (5). As we go down the path of sin, our penalty gathers momentum just as goodness brings its own capacity for greater goodness.