A.T. Robertson Commentary Revelation 20:6

"Blessed and holy is he that hath part in the first resurrection: over these the second death hath no power; but they shall be priests of God and of Christ, and shall reign with him a thousand years." — Revelation 20:6 (ASV)

Blessed and holy (μακαριος κα αγιος). A fifth beatitude (1:3; 14:13; 16:15; 19:9) already and two more to come (22:7,14, seven in all). Here αγιος is added to the usual μακαριος. The second death (ο δευτερος θανατος). The spiritual death of 2:11; 20:14; 21:8 in contrast to the first or physical death. This language raises a question about the interpretation of the first and the second resurrections, whether both are of the body or one of the spirit. There seems no way to reach a solid conception about it. In 1 Corinthians 15:23 there is no mention of the resurrection of any save "those of Christ" (ο του Χριστου), though the end follows (verse 24). However, Paul elsewhere (Acts 24:15) speaks of the resurrection of the just and of the unjust as if one event.

Priests of God and of Christ (ιερεις του θεου κα του Χριστου). As in 1:6; 5:10; 22:3,5.

Shall reign with him (βασιλευσουσιν μετ' αυτου). As promised in the same passages. The servants of God are to be priests with Christ and to reign with him (Matthew 19:28). In 5:10 επ της γης (upon earth) occurs, but this item does not appear here. "No hint is given as to where this service is to be rendered and this royalty to be exercised" (Swete).