The passage this question references is Genesis 3:23-24, which says, “So the LORD God banished him from the Garden of Eden to work the ground from which he had been taken. After he drove the man out, he placed on the east side of the Garden of Eden cherubim and a flaming sword flashing back and forth to guard the way to the tree of life.”
For many years I saw the banishment of Adam and Eve from the Garden of Eden simply as God’s punishment being placed on them. While this banishment was indeed a definite consequence of, and punishment for, their sin, I believe it was much more than that.
It appears to me that God expelled Adam and Eve from Eden as an act of His grace as well. The key to understanding this view is to look at the passage in its context, especially in light of the previous verse: “The LORD God said, ‘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.’ So the LORD God banished him from the Garden of Eden” (Genesis 3:22-23, emphasis mine).
Other verses, from the previous chapter, are also important in shedding light on this subject: “The LORD God made all kinds of trees grow out of the ground—trees that were pleasing to the eye and good for food. In the middle of the garden were the tree of life and the tree of the knowledge of good and evil. And the LORD God commanded the man, ‘You are free to eat from any tree in the garden; but you must not eat from the tree of the knowledge of good and evil, for when you eat of it you will surely die’” (Genesis 2:9, 16-17).
We learn from these verses that Adam and Eve had God’s permission to eat of every tree in the garden, except for one—“the tree of the knowledge of good and evil.” Therefore, we can conclude that they did have complete permission to eat from “the tree of life.”
After they disobeyed God’s clear command—“You must not eat from the tree of the knowledge of good and evil”—God, in His mercy, made it impossible for them to then eat from the tree of life. He did this by banishing them from the garden, and even prevented any possible return to Eden by placing “cherubim and a flaming sword flashing back and forth to guard the way.”
It seems apparent that God did not want any possibility that mankind, after falling to sin, would then eat of the tree of life and thereby live forever in that fallen state. As He said, “He [Adam] must not be allowed to reach out his hand and take also from the tree of life and eat, and live forever.”
“So the LORD God banished him from the Garden of Eden.” Had the Lord not done this, and Adam and Eve had eaten from the tree of life in their fallen state, mankind would have suffered eternal separation from God, without any hope of reconciliation.
This then appears to be a merciful act on God’s part. Thus, since their eternity had not been sealed, the Lord was able to provide a means of reconciliation for mankind. Yet the cost to the Father was the death of His one and only Son.
And this was His most gracious act of all!
“The LORD is compassionate and gracious, slow to anger, abounding in love. He does not treat us as our sins deserve or repay us according to our iniquities. For as high as the heavens are above the earth, so great is his love for those who fear him” (Psalm 103:8, 10-11).