From the moment Adam caved to temptation and ate from the forbidden tree, he and his descendants have been cursed by death. But the Bible speaks about death in a number of ways, and these are often confusing. For example, if those who reject the Son will not see life (John 3:36), how are they resurrected into everlasting contempt (Daniel 12:2)? This can be understood when we recognise that, rather than just being the cessation of consciousness, death is actually a separation. There are, therefore, four kinds of death.
1. Spiritual death-
Spiritual death is the default state of a post-fall human being. It is a separation from God that lasts until we are saved by his grace (Ephesians 2:4-5; Colossians 2:13).
2. Death to sin and the world-
Romans 6:2 tells us that if we have "died to sin", we cannot continue to live in it. To die to sin is to be separated from it by grace of God.
3. Physical death-
Physical death is the separation of the spirit from the body. The body, effectively being a shell, returns to the Earth, and the spirit returns to God who gave it (James 2:26; Ephesians 12:17).
4. The second death-
The second death is defined in Revelation 20:14 and 21:8. It is the lake of fire, known as Hell. It is the complete and irreversible separation from God and all his love.
Most people will experience physical death once, at the end of their lives. There are exceptions for rapture (1 Corinthians 15:51-52), and of course for examples of resurrection such as Lazarus (John 11:1-44), however spiritual death, as cited in Ephesians 2:4-5 and Colossians 2:13, is reversed the moment one is saved by Jesus' grace. The second death also cannot harm a believer (Revelation 2:11; John 11:25). This contrasts death, i.e. separation, with life, in which things which were separated by sin are reunited permanently. Eternal life is when we, as believers, are raised up to the Lord, where we will spend eternity walking closer with Him than even our ancestor, Adam, walked in the Garden.