The first resurrection

“Blessed and holy are those who have part in the first resurrection. The second death has no power over them, but they will be priests of God and of Christ and will reign with Him for a thousand years." Revelation 20:6
The first resurrection is not an event. If it was, it would probably belong to the widow of Zarephath’s son (1 Kin. 17:22). But Jesus is spoken of as being “the firstfruits of those who have fallen asleep” (1 Cor. 15:20), i.e. those who have died. His resurrection is different from all the previous resurrections – Jairus’ daughter, Lazarus, etc. They returned from death to life, but in their mortal bodies. Jesus rose from the dead in His immortal body, never to die again. This is the body that we look forward to receiving (1 John 3:2).
Rather, the first resurrection refers to a group of people: those who believed in Christ and surrendered their lives to Him while they were in their mortal bodies. This includes believers who have already died, and those who will be raptured alive into heaven. “For the Lord Himself will come down from heaven, with a loud command, with the voice of the archangel and with the trumpet call of God, and the dead in Christ will rise first. After that, we who are still alive and are left will be caught up together with them in the clouds to meet the Lord in the air. And so we will be with the Lord forever” (1 Thess. 4:16-17).
Those who have part in the first resurrection, are born twice. They do not need to fear the second death – as those who were born once (physically) and were not born again (spiritually).