-->
A reference to the natural law instituted by God, whereby a person who persistently adheres to false beliefs and refuses to listen to the voice of truth gradually loses the ability to perceive the truth, "so that finally, as it were, a seal is set upon his heart" (Raghib). Since it is God who has instituted all laws of nature - which, in their aggregate, are called sunnat Allah ("the way of God") - this "sealing" is attributed to Him: but it is obviously a consequence of man's free choice and not an act of "predestination". Similarly, the suffering which, in the life to come, is in store for those who during their life in this world have wilfully remained deaf and blind to the truth, is a natural consequence of their free choice - just as happiness in the life to come is the natural consequence of man's endeavour to attain to righteousness and inner illumination. It is in this sense that the Qur'anic references to God's "reward" and "punishment" must be understood.
All actions are referred to God. Therefore, when we get the penalty of our deliberate sin, and our senses become impervious to good, the penalty is referred to the justice of God.
The penalty here is the opposite of the prosperity referred to in n 5. As we go down the path of sin, our penalty gathers momentum, just as goodness brings its own capacity for greater goodness.