Blessed and set apart he who is now having a part in the resurrection the first; over these the second death now has no power, but they choose in the future to be priests of God and of Christ and in the future, they reign with Him for a thousand years.
This speaks of the rapture. “The resurrection the first”
speaks of what occurs first in time with nothing else coming before it in time or in a series. There are no partial resurrections, just the resurrection the first. The second resurrection is of the dead. It occurs immediately before they are judged at the Great White Throne Judgment.
When Jesus returns, He gathers the people of the earth and
the sheep (the righteous) enter his kingdom, the goats (the evil ones) will be summarily dispatched and killed in judgment.