"7 Now war arose in heaven, Michael and his angels fighting against the dragon. And the dragon and his angels fought back, 8 but he was defeated, and there was no longer any place for them in heaven. 9 And the great dragon was thrown down, that ancient serpent, who is called the devil and Satan, the deceiver of the whole world—he was thrown down to the earth, and his angels were thrown down with him. 10 And I heard a loud voice in heaven, saying, “Now the salvation and the power and the kingdom of our God and the authority of his Christ have come, for the accuser of our brothers has been thrown down, who accuses them day and night before our God. 11 And they have conquered him by the blood of the Lamb and by the word of their testimony, for they loved not their lives even unto death. 12 Therefore, rejoice, O heavens and you who dwell in them! But woe to you, O earth and sea, for the devil has come down to you in great wrath, because he knows that his time is short!”"
Revelation 12:7-12
The full force of the idea of Satan accusing the saints is brought out in a study of the first two chapters of the book of Job, where we are shown the Adversary in the presence of God speaking against Job, accusing him before God. (Significantly enough, an ancient Jewish tradition holds that Satan accuses men all the days of the year except on the Day of Atonement!) This accusation before God has its counterpart also in our hearts, in the sense of guilt and condemnation that can often prostrate us with fear and anxiety. There is one full and sufficient answer to it: the death and victory of Christ. John says, 'They overcame him by the blood of the Lamb...' i.e. 'on account of the blood of the Lamb', or 'by virtue of that blood having been shed'. The meaning is that their victory over Satan was grounded in, was a consequence of, His having shed His precious blood; without that, the Adversary's charges against them would have been unanswerable. But we must not forget the rest of what John says, 'and by the word of their testimony...'. It is because they have given a faithful testimony, even unto death, that they are victorious. The victory of Christ is appropriated, they stand in the virtue of the blood of the Lamb, only when a true and active response of faith is made in terms of a moral surrender of the will of God. In other words, this does not 'work' in the believer's experience unless and until the objective reality of the victory of the cross is met by the subjective consent of our faith 'that the effects of His death and resurrection should be imparted to us'. This consent is a consent to die. Our 'death' is the answer of faith to His. Only thus does His victory become ours.