The first prohibition given to man has within it all the features of the future Law of Israel, and marks the beginning of man’s training for his moral calling. It begins human history and shows all future generations the path in which they are to walk. From the tree of knowledge of what is good and what is evil you shall not eat.
This Tree of Knowledge of Good and Evil is not so named because it conferred the ability to distinguish between good and evil. Freedom of choice is the hallmark of man, and without the ability to distinguish between good and evil there can be no choice. There would have been no meaning to any prohibition that preceded this basic awareness.
Rather, the tree is named for its initial role in shaping man’s knowledge of good and evil. The tree, and the prohibition associated with it, was to teach man what is good or bad for him, and how he should distinguish between them. The tree is described as appealing to man’s taste, imagination and contemplative mind. These all drew man to the tree and tempted him. Yet, G-d forbade man to eat of the fruit of this tree. In other words, partaking of this fruit was defined as being bad for man. This tree, then, was to remind man of that teaching on whose observance man’s whole eminence depends. A person’s senses, imagination and intelligence may tell him that a certain thing is good — but that thing may conflict with his higher calling. This tree of knowledge of good and evil teaches us how to determine what is good and evil: namely, that we should not rely on our own senses, imagination, or intelligence, but rather obey the revealed Will of G-d. Only then will we have followed good. The form of the prohibition is also significant. As explained above, the prohibition was not a rational one. Indeed, the rational mind resisted it. Moreover, it was a dietary prohibition, transmitted as an oral tradition. It was communicated directly to Adam, yet Eve and her descendants were commanded to obey it. These characteristics of the law — a dietary prohibition, with no rational purpose, transmitted orally — are precisely those aspects that our sensual nature and mocking neighbors have taken issue with. And they are all contained in this very first prohibition, the one which begins the development of man as a free, choosing being.
The tree is also named for its subsequent role in the final result: Through this tree, knowledge of good and evil will be acted upon and decided; through its fruit, man will choose what is good or bad in his own perception. We all still stand before this tree of knowledge, as did Adam and Chava in their day. Faced with the demands of G-d’s moral law — at times incomprehensible to us — we decide whether to obey bodily sensuality, imagination of the sensual mind, and our own limited intellect, or to be mindful of our higher calling and heed the voice of G-d.
Sources: Commentary, Bereishet 2:9, 16