Charles Spurgeon Commentary Genesis 3:22

"And Jehovah God said, Behold, the man is become as one of us, to know good and evil; and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever-" — Genesis 3:22 (ASV)

And the LORD God said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever:

That would have been a horrible thing, for man to be incapable of death, and so to continue forever in a sinful world. It is by passing through death that we come out into the realm of perfection.