The Alter Rebbe now goes on to explain why in Gan Eden, when the soul is not encumbered by a body, the light of Keter cannot be manifest, whereas — paradoxically — this revelation becomes possible only in the World to Come at the time of the Resurrection, when the soul is once again invested within a body.

(For, as is well known,33 the determining opinion is that of the Ramban,34 who states that the ultimate reward will be specifically at the time of the Resurrection, when the soul will again be found within a body.)

כי נעוץ תחלתן בסופן דוקא

For35 “Their beginning (i.e., the loftiest initial level) is wedged in their end.”

This is explained in the teachings of Chassidut36 as follows: “Beginning” refers to a level of Divinity that utterly transcends the evolvement of any created worlds. This level of Divinity is wedged in the last level preceding the creation of the evolving worlds, the Sefirah of Keter. Keter is revealed only in the “end” of all worlds — i.e., within this physical world — during the time of the Resurrection. Gan Eden, by contrast, is incapable of receiving this transcendent level of revelation in an internalized manner.

Thus, while the lesser radiance that is muted to match the respective limitations of the evolving worlds can be absorbed by the soul (in Gan Eden) in its disembodied state, the transcendent radiance issuing from Keter is revealed to the soul only when it is clothed within a body.

וסוף מעשה במחשבה תחלה כו׳, כנודע

Likewise, as is known,37 “The final deed — i.e., the last stage of creation: this physical world — was first in thought….”

Thought and creation both have aspects that are “first” and “last”; the “last” (i.e., lowest) level of creation, which is this world, is rooted in the “beginning” (i.e., in the highest level) of the Divine thought.

This is why specifically the deeds performed in this “last” world of creation, while the soul is clothed in a physical body, are able to elicit and draw down the radiance of Keter. As explained here by the Alter Rebbe, this refers to the mitzvah of tzedakah, as well as to mitzvot in general, all of which are termed “tzedakah”.38 For it is the performance of physical mitzvot in this material world that arose first in G‑d’s thought and will, at the level of the Divine Keter, for the physical mitzvot are the ultimate purpose of creation.