Psalm 82. Let’s set the scene:
God stands amidst what might be called His divine council in heaven. God is of course supreme, but his angels are also there. Using language which is elsewhere in scripture, the Psalmist describes these angels as “elohim” (gods) and “sons of the most high.”
This divine council language is also used elsewhere in scripture. Psalm 89:5-7 speaks of a council of “holy ones” in heaven–sons of God. Job likewise speaks of the sons of God (including Satan) presenting themselves before God in heaven.
In Psalm 82, these angelic beings (seemingly fallen demons) are being chastised by God for their evil influence upon the nations. This chastisement carries a warning of apocalyptic judgment:
“‘You are gods, And all of you are sons of the Most High. Nevertheless you will die like men And fall like any one of the princes.’ Arise, O God, judge the earth! For it is You who possesses all the nations” (Ps. 82:6-8, NASB).
Unlike with humans, death is not a natural part of the angelic life. Yet in this warning, God claims that these fallen angels will die just like men do. In the human experience, and in the Hebrew belief system, death is a cessation of life and personality. In Psalm 82, we learn that this death is the ultimate fate of those angels who mismanaged their responsibilities and rebelled against God. Since the unredeemed will share in the place of consuming fire “prepared for the devil and his angels” (Mat. 25:41), it will likewise be the fate of every human being who is not found to be in Christ.
Thus, final punishment for both men and angels consists of this–cessation of existence.