In Genesis 2 God establishes the Garden of Eden. In its center he plants two trees: ‘The tree of life and the tree of the knowledge of good and evil’. (Gen 2:9)
God tells Adam that he is free to eat of any tree in the garden except the tree of the knowledge of good and evil (2:16-17). This command implies that it is alright for Adam and Eve to eat of the tree of life. Also it shows in Genesis that access to the tree of life provided immortality. Thus as long as Adam and Eve have access to this tree, they enjoy immortality.
However, after Adam and Eve disobey God and eat from the tree of the knowledge of good and evil, God banishes them from the garden, removing them from access to the tree of life, thus taking away their immortality and introducing the human race to death. God then places cherubim to guard the way back into the garden, stating explicitly that the cherubim are to keep them from accessing the tree of life (Gen 3:24).
The truth – The human race is now exluded from access to the tree of life and that all people, therefore , will experience death.
The tree of life emerges again in Revelation, where access to it once again represents eternal life or immortality. In Revelation 2:7, God tells the church at Ephesus that “To him who overcomes, I will give the right to eat from the tree of life, which is in the paradise of God”