God is the fountain of life; and when one chooses the service of sin, he separates from God, and thus cuts himself off from life. He is “alienated from the life of God.” Christ says, “All they that hate Me love death.” Ephesians 4:18; Proverbs 8:36. God gives them existence for a time that they may develop their character and reveal their principles. This accomplished, they receive the results of their own choice. By a life of rebellion, Satan and all who unite with him place themselves so out of harmony with God that His very presence is to them a consuming fire. The glory of Him who is love will destroy them.
At the beginning of the great controversy, the angels did not understand this. Had Satan and his host then been left to reap the full result of their sin, they would have perished; but it would not have been apparent to heavenly beings that this was the inevitable result of sin. A doubt of God’s goodness would have remained in their minds as evil seed, to produce its deadly fruit of sin and woe.
But not so when the great controversy shall be ended. Then, the plan of redemption having been completed, the character of God is revealed to all created intelligences. The precepts of His law are seen to be perfect and immutable. Then sin has made manifest its nature, Satan his character. Then the extermination of sin will vindicate God’s love and establish His honor before a universe of beings who delight to do His will, and in whose heart is His law.
– The Desire of Ages, pg. 764