"God's Essence is also incomprehensible to the blessed in Heaven."

In Heaven, we retain our human nature. It is natural for a human to be limited. Naturally, humans don't know everything. However, it is God's nature to be without limit. There is a change in quality when one goes from countable to countless, not just a change in quantity – therefore the finite cannot fully comprehend the infinite. Despite the many helps God gives us (reason, the world, etc.), we are still in some Climacusian dream where the final rung of the ladder to understanding God is missing, and indeed cannot be filled in.

Some faithful followers of this Blog will ponder, doesn't this dogma sound a lot like "God's Nature is Incomprehensible to Men"? What we have is two facets of God: what He does and who He is. Nature is in reference to the drives of God, what are His motivations? Essence goes deeper. Essence is who God is underneath the external appearances and actions. One could say it is natural for a man to want food, but that the essence of Man is his being a child of God. Earlier then, we looked at how God's actions are incomprehensible to men. Now we look at how, even in Heaven, the very core of God's being is incomprehensible to men.

Putting all this another way, God is, by nature and essence, a mystery. One of the qualities of God as mankind sees Him is mystery. God reveals this quality in His name (CCC 206) and we as Christians live out this quality by living out our Christian life. The mystery of God doesn't go away after death just as the mystery of a spouse doesn't disappear after marriage. Indeed, marriage is the start of living out the mystery of this other person, and death (in baptism) is the start of living out the mystery of our God.

Further Reading: The Wisdom of God is beyond fully comprehending (Sirach 24).