A Brief History of Salvation
written by Craig Rusbult, Ph.D.

 
      Human Sin and Three Results
      God offered the gift of full life (with relationship, quality, and immortality) to Adam, but with one rule:  in Genesis 2:17, God says "you must not eat from the tree of the knowledge of good and evil."  In Genesis 3:6, tempted by a creature who already had fallen into sin and rebellion, Eve and Adam ate from this tree of knowledge, choosing to make moral decisions for themselves, independent from God, instead of trusting and obeying God.
     This fall into sin, which broke Adam's part of a conditional if-then covenant with God, produced three results:  The immediate intrinsic result of disobedience was a loss of their innocence and their intimate relationship with God, so in Genesis 3:7-13 we see spiritual death.  Then two judicial results were decreed by God, in Gen 3:14-24.  The judicial penalty for sin begins with a decrease in quality of life (Gen 3:14-19,23) for humans.  And the ultimate penalty (Gen 3:22,24) allows physical death for humans after God removes the life-protecting tree of life:  God says, "The man has now become like one of us, knowing good and evil.  He must not be allowed to reach out his hand and take also from the tree of life and eat, and live forever."  The second sentence clearly explains the purpose of the action:  to prevent disobedient sinners from living forever, God removed "the tree of life."
      I think this tree symbolizes the supernatural full protective power that continually was being provided by God.  When the supernatural full protection was removed by God due to their sin, Adam and Eve began to perish, with natural processes temporarily allowing life while gradually (during the "yom" of Genesis 2:17 that can be translated as "day" but can also indicate a longer period of time) leading to their eventual death.  The divine penalty of death in Genesis 3:22 is a key to understanding God's response to sin, and His plan of salvation.

      A Brief History of Sin and Salvation
      Let's look at our problem (human sin leading to human death) and God's solution (for converting sin and death into salvation and life).
      SIN and DEATH:  The fall into sin (in Genesis 3) produced three results, one intrinsic and two judicial:  a decrease in relationship with God, a decrease in quality of life, and a loss of everlasting life.  Through God's grace and power, the initial gift of life (with relationship, quality, and immortality) was offered to Adam, but was lost by his sinful disobedience.
      SALVATION and LIFE:  We had sinned and thus earned death.  We needed a savior, and God is merciful, so the gift of life (with relationship, quality, and immortality) was won back for us by our savior.  On the cross, in a substitutionary atonement, Jesus Christ accepted for us the penalty of death that each of us earns by our sinful disobedience, and Jesus (by living in sinless obedience to the Father during His life on earth, before His sacrificial death) earned the right to make His own Eternal Life available, as a gift of grace, to all humans who will accept: "The wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord." (Romans 6:23) The gift of everlasting full life — both spiritual and physical — that in Genesis was temporarily taken from us (because of sin) will be permanently given back to us (because of Jesus) in Revelation: "To him who overcomes, I will give the right to eat from the tree of life, which is in the paradise of God. ... Blessed are those who wash their robes, that they may have the right to the tree of life and may go through the gates into the city." (Revelation 2:7, 22:14)   At that time, after our resurrection in heaven, God's goal of "no sin and no death" will be permanently actualized.

a summary:  The "tree of [everlasting] life" was (and will be) a supernatural gift from God.  God gave the tree of life to humans (in Gen 2:9), temporarily removed it (Gen 3:22) due to the disobedient sin of humans, and will give it back to humans (Rev 2:7, 22:1-2,14) through the salvation that Jesus earned for humans and offers to us (John 3:16, Romans 6:23).