This is what must be done once Adam already tasted from the Tree of Knowledge and became mixed with evil. Then the process of refining is necessary until the evil is separated out by removing all sparks of holiness within the Kelipah.
All of this refinement process is by way of Chochmah, for “Through Chochmah it becomes refined,” since it contains within itself also Gevuros-Severities, in order to allow for “Yud-Hei sends him suffering,” and as is written, “Just as a man rebukes his son, so too, Hashem rebukes you.”
The letters of Yud and Hei correspond to Chochma (Yud) and Bina (Hei). The fact that suffering comes from these two levels is because they contain the Gevura-Severity of Chochma, which is what affects purification and refinement, and suffering is for the purpose of purification from sin (or physicality).
Which is not the case regarding the level of Keser-Divine Will, which is above Chochmah, for Keser is pure Rachamim-Mercy, and on that level “Darkness is equivalent to light.” (Tehillim 139:12)
Since, at that level, spiritual darkness does not have any effect, there is also no need for the removal of that darkness. This is why purification comes from Chochma, since it is the first level that is affected by unholiness, and therefore sees the need to remove unholiness.
Therefore, there is a concern that, “Lest he stretch his hand forth and take also from the Tree of Life,” and then “he will live forever,” even if he sins, since “If you are righteous, what does that offer Him.”
Since he is on the level of Pnimius-internalization, therefore the evil that is bound and fixed within him would also be sustained, which would be the opposite of the ultimate intent of creation.
As is written in the Zohar regarding Rebbi Acha in the village of Tarsha during a plague: He removed the judgement against them through the recitation of the passages of the Ketores [Incense offering] in the place where the plague struck, and thereby stopped the plague.
He was then told from Heaven that this was not appropriate, since the people there remained in a state of guilt, and hadn’t done Teshuva (repentance) for their sins.
If he would have first inspired them to do Teshuva and then removed the plague by reciting the passages of the Ketores, that would have been fine, but to stop the plague while they are still sinning is only adding life to unholiness.
(The end of the story is that he was told from Heaven to go back to the city and bring the people to repent, which he did, and the people stopped sinning and became devoted to serving Hashem).
We see from this story that as long as someone is connected to sin and evil, then granting him additional life also gives additional life to unholiness, since it becomes mixed into the person.
Therefore, immediately, Hashem “sent him [Adam] from Gan Eden to work the land from which he was taken.”
This ‘work’ is the process of spiritual refinement of the physical world through seeding, plowing and harvesting, until grain and produce are ready for consumption.
Then, afterwards, when one eats from that food and uses the energy to say, “Hear Yisrael, Hashem is our G-d, Hashem is One, and you shall love Hashem...” he refines and elevates that food and the entire earth that the food is derived from.
At that point, he [Adam] needed to physically traverse the “earth which he was derived from,” and to refine the sparks of holiness that fell into it from his sin by eating there from its produce and using that energy to serve Hashem.
Originally, Adam and Chava were lived in the semi-spiritual place called “Gan Eden,” and didn’t need to work the “land” of that place for it to produce food. After the sin of the Tree of Knowledge, the entire world descended spiritually and the earth became coarser. Because of his sin, Sparks of Holiness fell into everything in the physical world, including the physical earth. In order to extract the Sparks of Holiness from the earth, this process of working the ground to produce food was needed, so that by eating the produce that came about with his effort and sweat, and using that energy to serve Hashem in prayer would elevate those sparks.
