And I heard a loud voice in heaven saying: “Now have come the salvation and the power and the kingdom of our God, and the authority of His Christ. For the accuser of our brothers has been thrown down—he who accuses them day and night before our God. — Revelation 12:10

The accuser of the brothers has been thrown down, and they overcome him by the blood of the Lamb and the word of their testimony. Who shall bring any charge against God's elect? It is God who justifies. Christ disarmed the rulers and authorities, triumphing over them in the cross. The accuser may still whisper, but he's been silenced at the cross.