Blessed and holy is he that hath part in the first resurrection: on such the second death hath no power, but they shall be priests of God and of Christ, and shall reign with him a thousand years. Blessed - Μακαριος· Happy. And holy; he was holy, and therefore he suffered for the testimony of Jesus in the time when nothing but holiness was called to such a trial.
The first resurrection - Supposed to be that of the martyrs, mentioned above.
The second death - Punishment in the eternal world; such is the acceptation of the phrase among the ancient Jews.
Hath no power - Ουκ εχει εξουσιαν· Hath no authority - no dominion over him. This is also a rabbinical mode of speech. In Erubin, fol. 19, 1; Chagiga, fol. 27, 1: "Res Lakish said, The fire of hell hath no power over an Israelite who sins. Rab. Elieser says; The fire of hell hath no power over the disciples of the wise men."