Adam was commanded to eat from all other trees, include the Tree of Life. [Surely], he ate from it. How was death decreed on him?
Riva #1, Moshav Zekenim (22): Perhaps the tree helps only one who already ate from Etz ha'Da'as, like some medicines help only sick people. 1
Riva #2: Perhaps he did not eat from the Tree of Life, for he was in Gan Eden only a short time.
Riva #3: Perhaps he did not eat from the Tree of Life, for before eating from Etz ha'Da'as, he did not know to distinguish it from the other trees.
מה משמעות האכילה בגן עדן?