Regeneration

"Regeneration is indispensably necessary before any soul can enter Heaven. In order to love spiritual things a man must be made spiritual. The natural man may hear about them, and have a correct idea of the doctrine of them, but he cannot love them (2 Thess. 2:10), nor find his joy in them. None can dwell with God and be eternally happy in His presence until a radical change has been wrought in him a change from sin to holiness; and this change must take place on earth."

~ Arthur Pink, "Regeneration or The New Birth"