Charles Spurgeon Commentary Genesis 2:9

"And out of the ground made Jehovah God to grow every tree that is pleasant to the sight, and good for food; the tree of life also in the midst of the garden, and the tree of the knowledge of good and evil." — Genesis 2:9 (ASV)

That tree of life in the middle of the earthly paradise was to be symbolic of another tree of life in the paradise above, from which the children of God shall never be driven as Adam and Eve were driven out of Eden.