Biblical explanation
Revelation 20:14 gives the clearest definition: "Death and hell were cast into the lake of fire. This is the second death." The first death is the death experienced by human beings in the present world. The second death occurs after the final judgment. Revelation 20 describes two resurrections. Those who participate in the first resurrection are blessed and the second death has no power over them (Revelation 20:6). After the millennium, the remaining dead are resurrected for judgment. Satan is released, rebellion occurs, and fire comes down from God (Revelation 20:7-10). Then the lake of fire is called the second death. Revelation 21:8 again identifies the lake of fire as the second death. The second death is therefore not merely another stage of ordinary mortality. It is the final, irreversible destruction of sin and those who ultimately cling to it.
Key takeaway
Discipleship applies the gospel to the whole life: body, mind, relationships, work, finances, and worship. Healthy choices and faithful habits do not earn salvation; they are grateful stewardship of the life God has entrusted to us and practical ways to serve others.