The Greatest Challenge
Adam and Eve, the first humans, fashioned by G‑d Himself, failed the very first test they were presented, with repercussions that last to this day.
Commentators have grappled with trying to understand how people of such prominence could fail their one and only test on the very day they were created? What was so enticing about that fruit whose eating unleashed universal degradation and death?
The Rebbe explains that, precisely because G‑d’s commandment was their only challenge, Adam and Eve experienced the greatest enticement according to the rule that the greater the mitzvah, the greater the resistance to it.
However, we still have to understand how the serpent convinced the first humans that eating the fruit was the ok thing to do.
Don’t Touch!
Our Sages provide us with the answer when they refer to Eve’s having added a new prohibition of her own that she should not even touch the tree. When the Serpent pushed her against the tree, he said “Just as there is no harm in touching the tree, there will be no harm in eating from the tree.”
Commentators ask, if Eve added the prohibition against touching the tree, how could the Serpent have convinced her that it was acceptable to eat the fruit of that tree as well?
The answer is that Eve initially was so sensitive to G‑d’s command not to partake of the forbidden fruit that she concluded that she must take extra precautions not to succumb to the temptation to do just that. This is akin to the law that a Nazir, a person who takes a vow to abstain from wine, must not even go near a vineyard lest he be tempted to break his vow.
When the Serpent pushed Eve against the tree, his intention was to convince her that she needn’t be so concerned about possible transgressions and did not need to take precautionary measures.
The Slippery Slope
The Serpent’s disingenuous argument was that she was such a lofty person, created and fashioned by G‑d Himself, endowed with superior intelligence and infused with a lofty Divine soul, that she needn’t be fearful that she would succumb to temptation.
Once she accepted the serpent’s premise, that great intellectuals and spiritual people do not need to take precautionary steps, the Serpent was ready to convince her that she could even partake of the forbidden fruit.
His next insidious argument was that the commandment against eating the fruit of the forbidden Tree of Knowledge was itself only a precautionary measure. The Serpent argued that there was nothing inherently wrong or immoral with eating the fruit of the Tree of Knowledge. On the contrary, this fruit would only enhance her intellectual and spiritual powers. The “real” reason for the commandment, he suggested, was that it was only a precautionary measure to prevent one from indulging in the immoral behavior that the knowledge of evil can bring.  Only lower-class people, said the Serpent, might be inclined to indulge in the activity they have come to know intellectually.
For example, it would not be proper for a young person to read books that deal with banned and harmful drugs. This would not apply to a mature person who delves into the subject academically and professionally, in a totally detached and unemotional fashion.
Once the Serpent convinced Eve that she needn’t be concerned with touching the Tree, he proceeded to convince her that she could partake of the fruit.  After all, wasn’t  she immune and impervious to the temptations that might ensue from eating that fruit? The Serpent convinced her that she was “above the fray” and that the commandment would only become relevant for her progeny, who would not be at the same intellectual and spiritual level she and Adam were on.
The Esrog
We can now understand the symbolism behind the assertion of the Midrash that the forbidden fruit was an Esrog.
What is so unique about the Esrog?
The Talmud explains that it is one of the only fruits that shares with the bark of the tree the taste of the fruit itself.
How are we to understand this teaching?
The tree is the means to the fruit, which is the end. Normally, we accord much greater significance to the end than to the means by which we achieve it. If we could circumvent the means and reach the end without it, we would eliminate the means entirely because it is only a vehicle. One who lives in close proximity to his place of work does not need to own a car to get to work.
The Esrog, in which the means (read: the tree) and the end (read: the fruit) are the same, suggests that the means also assumes an important, even indispensable role and must be respected, just as we would respect the end result.
The Ragatchover Gaon established this principle when he referred to the four actions that are needed in the offering of a sacrifice at the Bais Hamikdash: shechitah (slaughtering of the animal), kabbalah (receiving the blood), holacha (carrying the blood to the Altar) and zerikah (sprinkling the blood on the altar).
If a person had a forbidden thought during any of these activates it rendered the sacrifice unfit.   This was true even if it happened during the carrying of the blood to the Altar, which was only a means to an end and would have been dispensable if one slaughtered the animal next to the Altar. Yet, it is still considered to be an integral component of the offering of the sacrifice. The means in the performance of a Mitzvah assumes the weight and gravity of the Mitzvah itself.
Similarly, by forbidding the partaking of the Esrog, G‑d hinted to Adam and Eve that although this prohibition was merely a means to an end it was not to be trifled with.
Shabbos Transformation
We can now understand why our Sages state that if only Adam and Eve had waited the three hours to the onset of the Sabbath, they would have been permitted to eat the forbidden fruit. To Eve this was “proof” that the commandment was predicated on a person’s ability to withstand the pressure that comes from heightened knowledge of good and evil and not be affected by it. While G‑d wanted them to wait until they would be elevated by the holiness of Shabbos, the Serpent convinced Eve that she was already at that point.
The message for us today is that, as we are still in exile and have not yet arrived at the Sabbath of history, we still have to take rabbinic precautions seriously because they protect us from falling prey to all sorts of temptations.
However, with the imminent coming of Moshiach, when we will be elevated into the Shabbos mode of holiness, we will be able to elevate those things that we must distance ourselves from in the present era. We will be so infused and suffused with Divine knowledge that the evil of the world will be transformed into holiness and even the Serpent will be rehabilitated. This is hinted in the numerical value of the word nachash (serpent), which is 358 the same as Moshiach. This suggests that in the Messianic Age the Serpent which brought degradation and death in its wake will become a vehicle for holiness and life.