Genesis 3:22

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:

1. Prior to eating the fruit of the tree of the knowledge of good and evil Adam and Eve did not recognize the difference between good and evil. Now they did.
2. Knowing good and evil - understanding and being capable of distinguishing one from the other is a significant characteristic of the LORD God and His associates (whoever He spoke to when He said this).
3. Other beings were with the LORD God when He dealt with Adam and Eve following their transgression of His commandment.
4. There was another special tree in the Garden of Eden called "the tree of life," which, if eaten, would cause a person to live forever. Adam and Eve, at this point, had full access to this tree. It's not clear, however, whether Adam and Eve understood the tree's characteristics.
5. The LORD God, who had already promised Adam and Eve they would die if they ate from the tree of the knowledge of good and evil, intended to take measures to ensure that promise was fulfilled.
6. It seems reasonable to suppose, since the LORD God and His companions created a tree that enabled a being to live forever, that they possessed this quality, as well.
7. Either the LORD God did not want men and women to live forever, or He had other plans for accomplishing that following their limited lifespans (such as the resurrection).