'Second Death' in the Bible

He who has ears, let him give ear to what the Spirit says to the churches. He who overcomes will not come under the power of the second death.

Happy and holy is he who has a part in this first coming: over these the second death has no authority, but they will be priests of God and of Christ, and will be ruling with him a thousand years.

And death and Hell were put into the sea of fire. This is the second death, even the sea of fire.

But those who are full of fear and without faith, the unclean and takers of life, those who do the sins of the flesh, and those who make use of evil powers or who give worship to images, and all those who are false, will have their part in the sea of ever-burning fire which is the second death.