The Heart 7:100
Is it not evident to those who possess and inhabit the earth, which was transferred to them without a contract; and after the destruction of its former residents due to their sins and behavior, and after they moved away; that if We desired, We could cause them harm because of their sins and forbidden actions, like we did to their predecessors. And We closed and sealed them so they will not contain any good that gives absolute validity to their intelligence. And they do not sense with their ears or perceive a stern reprimand or reminder.
The sealing of the heart is like an impression on a coin. The heart conditions the brain. If the heart is bad, it will condition the brain to follow the way of destruction. A good heart will condition the brain to follow the way of health, productivity and creativity.