In Revelation Revelation 20:6, this is written:
holy are those who share in the first resurrection; the second death has no
power over them but they will be priests of God and of Christ and reign with
him for a thousand years. (New Jerusalem Bible)
Those who will take part in the first resurrection
and those who alive and remain when the Lord comes, are
blessed and holy because they are also saved from the full Wrath of God
which is the "second death" — God's eternal punishment for the sinners.
What is the second death?
Then Death and Hades were cast into the lake of fire. This is the second death.
(Revelation 20:14, NKJV)
The second death, is the
eternal punishment in the in the lake of fire.
This is the full payment of sin. The full wrath of God.