Note that these words are a repeat of what is written at the end of Revelation 20:4. The repetition serves to draw attention to these words; that is, John’s readers must not overlook the fact that their martyred brothers and sisters are today reigning in heaven in the very presence of God. Not Satan governs this world but the saints with Christ.
6 Blessed and holy is the one who shares in the first resurrection! Over such the second death has no power, but they will be priests of God and of Christ, and they will reign with him for a thousand years.