 We see in Genesis 3, verse 23, that Adam and Eve could not have access anymore. After they sinned, God says they cannot have access to the tree of life, lest they take of it and live forever. It was because of their sin, and it showed that sin separates us from the source of life. In Genesis 3.22, it says, "...the Lord God said, Behold, the man has become as one of us."