Eternal separation from God in the lake of fire. Revelation 20:14-15: And death and hell were cast into the lake of fire. This is the second death. And whosoever was not found written in the book of life was cast into the lake of fire. The first death is physical — the body's separation from the soul, the consequence of Adam's fall (Rom 5:12). The second death is final — the eternal conscious punishment of those whose names are not in the Lamb's book of life. Christ promises His own that they will not be hurt by the second death (Rev 2:11). The doctrine is among the hardest in Scripture and is among the clearest. The modern church's frequent flight from eternal punishment is a refusal of Christ's own teaching (Matt 25:46, these shall go away into everlasting punishment: but the righteous into life eternal). The same Christ who promised heaven warned of hell.