There is a medrash (from memory) that had they refrained from eating as they were commanded, they would have been allowed to eat after Shabbos. That is, since it was still the sixth day, it was still part of creation. As a result the fruit of the tree of knowledgs was not ripe. Had they waited, the decision to refrain would have been their own free will decision and would have become part of creation. Then, once creation was complete, they could have eaten the "ripe" fruit, digested it and made it part of their lives as an integrated whole.
It was the premature eating that "spoiled" creation and set us on the difficult path of trying to reach our potential.
This was the dilemma that Adam and Chava faced and of which the snake
took advantage. The commentators are bothered about how it was
possible for Adam and Chava to have transgressed G-d's word if they
were lacking ra and free choice. They were rational, needing only to
determine truth and falsehood - yet at the Tree they met their
Waterloo, the paradox of their very existence. One part of their
essence declared they were subjects of G-d, to follow His Will. One
part of their essence, created by G-d, was that they were to be like
G-d, determining their own will. It was His Will that they make their
own decisions yet it was also His Will that they follow the decisions
of G-d. And nowhere was this paradox more confusing then at the Tree,
where G-d was telling these beings, created to make decisions, not to
develop their ability to make decisions.
Adam and Chava knew that their state before the Tree was unacceptable,
not their final destiny. How, though, do they solve the paradox, unite
the decision-making of their wills with the decision-making of The
Will of G-d? It was in how they responded to the Tree that they would
find their answer, yet, on the surface, it was only a continuation of
the dilemma. To not eat would mean to follow Hashem, but where was
their own will? What about their own decision? To eat would mean to
follow themselves, but where was The Will of G-d? What about His
decision? What to do? How to answer the paradox, solve the riddle and
reach the essence beyond?
The essence of Adam before the Tree had to change and, in truth,
either decision was a path to the new level of man. If Adam and Chava
would have followed the word of G-d, they would have achieved olam
habah immediately. Their decision to follow G-d would have provided a
point of integration[23]. They chose, however, the other way[24].
It was not that Adam and Chava benefitted from their transgression. It
was not that G-d held back this special knowledge of tov and ra. The
situation as it was, was not permanent. On this sixth day of creation,
Adam and Chava would act, either in refraining from the Tree or
partaking, thereby culminating the creation specifically of the moral
universe. Whatever act was chosen would catapult man into the path
whereby s/he would complete him/herself. This was part of creation.
This path chosen would introduce the qualities necessary for the
needed growth. Adam and Chava, perhaps unfortunately[25], chose the
more difficult path.
[22]See also Rabbi J.B. Soloveitchik's "Lonely Man of Faith",
Tradition 7:2 for a different approach to this dichotomy of man. I
believe that the thoughts presented in this article are inherently
reconcilable with the words of the Rav.
[23]The concept that they were "naked in mitzvot", Bereishit Rabbah
19:6, may take on new meaning with this approach. It was this one
mitzvah that would have solved the dilemma.
[24]Applying the Tanhuma, which implies that it was set-up for man to
transgress, it would seem that this was the only way for man to move
beyond the stage of before the Tree. For reasons that we will not
investigate at this time, this was the method by which G-d created
this aspect of creation. How, though, do we explain the act of
disobedience? There is always the question of how to reconcile that
all is performed through the Will of G-d, yet we have free choice
even, unfortunately to do evil. Yet, in this case, this event may be
less of a paradox since it occurred during the week of creation. Since
this event shaped the very nature of free choice and reward and
punishment, the greater direction by G-d over the actions of man may
be accepted. Strangely, though, what is being said is that through an
act which G-d knew man would, by nature, have to perform yet that G-d
did forbid, the stage of the moral universe was created. This law that
it was impossible for man to follow, a most unique creation, is the
Tanhuma's explanation for the creation of this unique world where man
can reach his unique goals - a most interesting concept that you are
invited to further investigate. The approach in the body of the
article - that man had a choice and made a mistake - is, however, more
normative.