This 17th century Russian icon is of the Last Judgment when absolute Truth shines through all of Creation and the inner secrets and inclinations of every creature are shown forth for what they truly are. God is absolute Truth, and although completely merciful, He honors our choices, even when they are devastating in consequences. No one is forced against their will to enter the brightness of this brilliant and everlasting Truth, but those who live in this Truth and love God and this revelation, and have repented for all of the evil that they have done, are welcome to come and live with God and be illumined by His radiance. This is Heaven indeed. For those who choose it, everlasting growth in love is their future.
For those who find this revelation painful and have their hearts and minds closed and refuse to change, then the Glory of God is seen to them as a River of Fire and torment. It is the same brightness that illumines and enlivens all of Heaven, but it is perceived differently if we have become so negative that Light has become darkness to us, and darkness light. Frozen in negativity, those who choose Hell have frozen their hearts to never change.