When God judged Satan and the universe that was under him, God also must have judged the angels which followed him and the living beings on the earth during that age which joined him in his rebellion. After being judged, the rebellious angels became the "wicked spirits" in the air (Eph. 6:12, KJV margin), and the living beings became disembodied spirits, the demons lodging in the water with which they were judged.
Though Satan, the rebellious angels, and the demons were all judged by God, they are still moving and working today, because the judgment upon them has not yet been executed. One day it will be fully executed (Rev. 12:12; Matt. 8:29; Luke 8:31). Today, Satan can still go to God to accuse God's people (Job 1:6-12; 2:1-7; Rev. 12:10). He is still walking about on the earth, "seeking someone to devour" (1 Pet. 5:8), still working to blind people (2 Cor. 4:4), to deceive them (2 Cor. 11:14), to fill their heart (Acts 5:3), and to get an advantage of us (2 Cor. 2:11). He is still "the strong man," holding "his vessels" (Matt. 12:29). The rebellious angels are still "the world-rulers of this darkness" (Eph. 6:12; cf. Dan. 10:20), (some fallen angels are now imprisoned unto judgment—2 Pet. 2:4; Jude 6) and the demons are still the unclean and wicked spirits working on the earth (Matt. 12:43-45). The judgment upon them all needs to be executed.
God has judged Satan and all his followers. But this does not mean that God executed His judgment at the time He pronounced it. To condemn is one thing; to carry out the condemnation is another thing. God judged Satan and his followers before Adam was created, but the execution of this judgment is still going on. The execution of God's judgment will not be carried out by God Himself. God will not do this. No judge carries out the execution himself. He needs some executioners.
Who will execute God's judgment upon Satan and his followers? The executors will be the Christians, the church, the overcoming believers. Why hasn't the judgment on Satan and his followers been executed? Because God is waiting for the church to rise up. The Judge has made His judgment, but He is waiting for some executioners to carry it out. In Revelation 12 we see that the overcomers will execute God's judgment upon Satan. Moreover, day by day in our homes, whenever we are victorious, our victory is an execution of this judgment. God has declared His judgment upon the rebellious one. However, this judgment will not be carried out until the church rises up to do it. Now is the time for us to execute God's judgment over Satan.
Today the church must pray to "bind the strong man" and "plunder his house" (Matt. 12:29), fight against the wicked spirits in the air (Eph. 6:12), and cast out the demons (Matt. 17:21) wherever we see them working to damage people. God has judged the demons and confined them to the water, but He needs the church to bring in the age when the sea will be terminated (Rev. 21:1) and the demons which are now confined therein will have the judgment executed upon them (Rev. 20:13: the dead in the sea cannot be human beings, but must be the demons).
The Lord Jesus, when in the flesh as a man, began to execute God's judgment. He "was manifested, that He might undo the works of the Devil" (1 John 3:8). The Lord gave His disciples "authority" (Luke 10:19) over all the power of the enemy. When the disciples cast out demons, Satan fell from heaven (Luke 10:17-20). Through His death on the cross, He destroyed the Devil (Heb. 2:14). He has bruised the head of the old serpent. Now we, as His Body, must continue this execution, destroying the tail of the serpent. Through the church's executing work, the Devil will be "cast to the earth," and his angels will be "cast out with him" (Rev. 12:9). He will later be bound and cast into the bottomless pit (Rev. 20:2-3). Eventually, he will be "cast into the lake of fire" (Rev. 20:10). Then, the execution of God's judgment upon Satan and his followers will be completed.