In eternity past, God created angels with self-determination or free will, volition. See category on Angels.
The most perfect angel that God ever created is called Lucifer, the Son of the Morning. He was the most beautiful, intelligent, and personable of all the angels. He is a cherub which was, at that time, the highest rank of angels. Unfortunately, he became enamored with his own attractiveness and arrogance was found in his soul. His arrogance led him to act independently of God with his five “I wills.” Isaiah 14:12-15. Arrogance is a mental attitude sin and is the natural inclination of fallen creatures, angelic or human. Satan then convinced one-third of the angels to side with him against the grace and authority of God. We now have two categories of angels – elect and fallen.
““How you have fallen from heaven, O star of the morning, son of the dawn! You have been cut down to the earth, You who have weakened the nations! “But you said in your heart, ‘I will ascend to heaven; I will raise my throne above the stars of God, And I will sit on the mount of assembly In the recesses of the north. ‘I will ascend above the heights of the clouds; I will make myself like the Most High.’ “Nevertheless you will be thrust down to Sheol, To the recesses of the pit.” (Isaiah 14:12-15, NASB)
The negative volition of Satan and all fallen angels demands punishment from the perfect righteousness and justice of God. Satan and all fallen angels were tried and sentenced by the justice of God to the Lake of Fire. Matt. 25:41.
““Then He will also say to those on His left, ‘Depart from Me, accursed ones, into the eternal fire which has been prepared for the devil and his angels;” (Matthew 25:41, NASB)
Satan appealed his sentence and God permitted an appeal trial. A appeal trial is theologically deduced from Scripture in that God’s sentence of Matthew 25:41 has not yet been carried out. The sentence will be carried out at the end of the Millennium (the end of human history). Rev 20:10.
"And the devil who deceived them was thrown into the lake of fire and brimstone, where the beast and the false prophet are also; and they will be tormented day and night forever and ever." (Revelation 20:10, NASB)
In that appeal trial, Satan impugned the character of God by asking, “How can a loving God cast His angelic creatures into the Lake of Fire?” This is exactly the same thinking expressed by humans called human viewpoint. Human viewpoint does not consider the entire essence of God, but only His love. The perfect and eternal attributes of God cannot be unfair or prejudiced and cannot pass a false sentence.
God’s answer or rebuttal to Satan’s appeal was to create mankind a little lower than the angels, but with a similar soul structure containing a rational mind and free will or volition. Thus, human history began. God wanted to duplicate the conditions that existed when Satan sinned and one-third of the angels chose to follow him in rebellion. Since free will was the issue for angels and free will is an attribute of the soul, then mankind was created with a rational soul similar to the angels, except without their greater physical attributes and capabilities.
Prior to the creation of mankind, God restored Satan's headquarters (planet earth) for man's occupation. Man was created to provide evidence and resolve the appeal. Man was created physically inferior to angels, but having a similar soul (mentality, volition, a conscience, emotion, etc.).
Every time a member of the human race chooses for God through the work of Jesus Christ on the Cross, the character of God is vindicated and Satan loses his argument. Technically, when the first unbeliever accepted Jesus Christ as their Savior, Satan lost his appeal.
The Old Testament speaks of Satan's formal appeal trial. The Church Age became an extension of God's rebuttal to Satan's appeal. In the Tribulation, we will have Satan's rebuttal of violence. The Second Advent of Christ will terminate the appeal trial.
We are here to glorify God by the execution of His plan, to have an invisible impact on history, to evangelize the human race, and perform certain spiritual functions (e.g., teaching doctrine, witnessing, etc.) in order to resolve the Angelic Conflict.
Elect angels function under the command of the Lord Jesus Christ for the divine purposes related to human history. Fallen angels function under the command of Satan to try to delay or disrupt the unfolding of God’s perfect plan.
The Angelic Conflict has a great deal to do with the earth and the behavior patterns and the thought patterns of kings, with policies they form as they carry out many concepts of Satan. It is Satan’s system to carry out a system of order in the human race which will try to prove that he is right.
But Satan always bites off more than he can chew and never produces the goods. Satan is responsible for much of the human good in the human race as well as internationalism and religion. Satan thinks he can set up a moral situation apart from God. He wants a perfect order like the Millennium will be, but independent of God. He cannot do it no matter how hard he tries.