In the garden, two trees stood before Adam and Eve: one offering life through dependence on God, the other promising knowledge gained through independence from Him. Sin was Adam doing “what was right in his own eyes,” and it cost humanity access to the tree of life. God’s banishment of Adam from Eden was itself an act of mercy, keeping him from eating of the tree and living forever in his fallen, sinful state.
Genesis already points toward the remedy: God clothed Adam and Eve with garments, and a flaming sword guarded the way back to Eden, foreshadowing the torn temple veil. In Christ’s death, that way is opened again. Revelation closes the Bible where Genesis began, with the tree of life restored, its leaves for the healing of the nations, and “those who wash their robes” given the right to eat from it and enter the city.