'Second Death' in the Bible

The one who has an ear, let him hear what the Spirit says to the churches. The one who conquers will never be harmed by the second death.'

Blessed and holy [is] the one who has a part in the first resurrection. Over this person the second death has no authority, but they will be priests of God and of Christ, and they will reign with him a thousand years.

And Death and Hades were thrown into the lake of fire. This is the second death--the lake of fire.

But [as] for the cowards and unbelievers and detestable persons and murderers and sexually immoral people and sorcerers and idolaters and all liars, their share [is] in the lake that burns with fire and sulphur, which is the second death.