The Judgment of Satan

The rebellion of Satan and his angels occurred eons ago. But you may have noticed that they still are active and are seeking to prevent us from serving Christ as we would. How can this be? Does not the almighty God have the power to stop them? This indeed is a great mystery.
Therefore let us leave the elementary teachings about Christ and go on to maturity, not laying again the foundation of repentance from acts that lead to death, and of faith in God, instruction about baptisms, the laying on of hands, the resurrection of the dead, and eternal judgment. (Hebrews 6:1,2)
Notice that the doctrine of "eternal judgment" is considered an "elementary" teaching. Certainly we are familiar with the judgment of Satan on the cross of Calvary. That is an "eternal judgment."
Calvary accomplished the "forgiveness" of our sins. But forgiveness of our sins is not sufficient to usher in the Kingdom of God. What good does it do to forgive our sins if we and everybody else keep sinning?
Obviously, if Satan, his angels, and the demons, still are free to corrupt God's creation, there must be a further step of judgment. Can you see that?
God has promised to put an end to sin. I am certain He does not mean by this that He is going to put an end only to the "guilt" of sin. In other words, we still can keep sinning but we no longer are guilty. This reminds us of the lawless-grace doctrine, doesn't it!
“Seventy ‘sevens’ are decreed for your people and your holy city to finish transgression, to put an end to sin, to atone for wickedness, to bring in everlasting righteousness, to seal up vision and prophecy and to anoint the most holy." (Daniel 9:24)