According to the second creation story in Genesis, when God placed Adam in the Garden of Eden he forbade him to eat from the tree of knowledge, saying that if he does he will be "doomed to die" (Genesis Chapter 2, verse 17. In Genesis Chapter 3, Adam and Eve are tricked by the serpent into eating from the tree of knowledge. After doing so they are expelled from the garden and denied access to the tree of life. Thus due to their disobedience, death comes into the world. The story is generally seen as an allegory. The "death" to which the story refers is not earthy death, which is inevitable as our bodies grow old, but death to our hopes of eternal life. It was the choice to take our lives into our own hands, rather than rely on God's providence, that made us forfeit life in heaven.
St. Paul explains that when Jesus Christ died and then rose from the dead, he reversed the effects of this original sin. "For just as in Adam all die, so too in Christ shall all be brought to life" (1 Corinthians, Chapter 15, verse 22). In Chapter 13 of the Gospel of Luke, Jesus explains that this salvation is not automatic. We must "repent". Otherwise we will "perish", or not enter into eternal life when we die.
This is contrary to the idea that we will be sent to hell. Rather we will simply be snuffed out of existence. Only those who seek to return to a life of reliance on God, and who admit their repeated failures to do so, will be granted the salvation that Jesus' death won for us.
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