Satan used the Old Testament law to accuse Old Testament saints. But because Jesus nailed the law to his cross the devil can’t use it against the New Testament saints. The Bible says in Revelation 12 that Satan was cast out of heaven for good never to accuse the saints before God ever again; because Jesus judged him at the cross along with sin: Rev.12:7-9 says “And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels, And prevailed not; neither was their place found any more in heaven. And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.” In the Old Testament era Satan had access to go back and forth into heaven even though he was not a holy angel anymore: Job 1:6 says “Now there was a day when the sons of God came to present themselves before the Lord, and Satan came also among them.” He was accusing Job and that’s what he was doing continuously throughout the entirety of Old Testament times. But Jesus says in Luke 10:18 “…I beheld Satan as lightning fall from Heaven.” This was prophetic of what would happen after the cross! Revelation 12:10 says “And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brethren is cast down, which accused them before our God day and night.” John 12:31-32 also says “Now is the judgment of this world: now shall the prince of this world be cast out. And I, if I be lifted up from the earth, will draw all men unto me.” Satan was cast of heaven by Christ finished work on the cross. It was there that Jesus destroyed Satans power: Colossians 2:15 says “And having spoiled principalities and powers, he made a shew of them openly, triumphing over them in it.” “It” meaning the cross. Don’t give Satan power that he doesn’t have. Understand your power over and against the works of the devil!