Frankly, though, the question can be asked, “That’s all well and good for the body, but how does it benefit the soul?” How is it to the soul’s advantage to purify the body? The quick answer lies in the fact that at bottom the soul’s primary function in this life is just that: to purify the body (by means of the mitzvah system) . And though it certainly has other functions once it leaves this world , the soul would obviously be rewarded for having carried out its vital mission here. The point remains, though, that the soul also blooms on its own in the here and now in very subtle but vital ways beyond our ken; but it doesn’t yet live up to its full potential . But there’s even more to it than that, though, which touches upon the whys and wherefores of the resurrection of the dead — which is of course the subject at hand. So let’s get back to that, and then return to what the soul gains from having purified the body.
Everyone has to have asked at one point or another why we must die — why G-d couldn’t have created a world in which mankind lives forever. After all, Adam and Eve would have been immortal had they not sinned, so the implication is that immortality was originally the rule. (Indeed, the very human search for immortality is often said to be rooted in the dream to return to the Garden of Eden and undo all the harm done by our having been cast out of it.) In any event, Adam and Eve’s having eaten from the Tree of the Knowledge of Good and Evil did indeed bring death into the world . Had they not done that, the soul would have purified the body right there and then, and our mission would have been accomplished from the first .
Thus, among the very many consequences of their sin was the fact that the soul was forced to carry out its primary task of purifying the body in the new context of mortality and slow progression – that’s to say, in the world as we now know it. For not only was immortality and purity undone with Adam and Eve’s sin: instantaneousness was, too. For while the world was created in a linear mode (in seven days, with one thing leading successively to another), that system was to have been undone had Adam and Eve not sinned. Thus everything — the soul included — is now forced to succumb to time and to the slow, plodding ways of life … and of death … due to Adam and Eve’s terrible error. Understand, though, that our “death sentence” has nothing to do with our own individual sins. After all, some utterly righteous and pure individuals who deserved immortality still and all die d because of that first sin . The point nonetheless is that death is a consequence of events and serves a purpose; and that G-d could certainly have created an immortal world but He did not for the above reason.
But let’s get back to the resurrection of the dead (one of the points of which is the fact that though death is purposeful for now it will be undone).
Though a lot of the impurity that infests the body starts to become undone with the desiccation that begins when the flesh returns to its elements, the process of purification is only completed when body and soul are reunited in the course of the resurrection . And that’s the greatest role of the resurrection. For that’s when “the soul will re-enter the body with all the strength of its good deeds, and with the gleam of Celestial Light it had acquired … in the Afterlife,”  as Ramchal puts it here. As it’s then, after the resurrection, that “the soul will emit a great Light which will utterly purify the body” and make it possible for it to be “healed of all the harm originally done to it” by its sins . And then finally after the resurrection, in the World to Come, the soul will be rewarded in full for its efforts back here, on earth. That also tells us, by the way, that there are actually two periods of reward and punishment: the Afterlife and the World to Come. So while20 the resurrection will indeed be staggering, tumultuous, and utterly otherworldly, it will still and all not be the great and cosmic “be all and end all” … the World to Come will. In a way, then, the resurrection will serve the same function in relation to the World to Come as this world does in relation to the Afterlife. In that both the resurrection and this world are byways and ports-of-call in which one is readied for his eventual destination. Our sages abridged the whole process by saying that “this world (and thus the period of the resurrection of the dead) is like a vestibule to the World to Come” (Pirkei Avot 4:16).
 This is consistent with Luzzatto’s remarks in The Path of the Just that “Our sages … taught us that we were created to delight in G-d and to enjoy the radiance of His Divine presence … in the World to Come …. And (that) the means to bring you to this goal are the mitzvot” (Ch. 1), suggesting that the mitzvot act as a kind of “steam” for the locomotion toward the ultimate end.
Ramchal cites Zohar 1 p. 115a (Midrash Ne’elam) here and later on as a depiction of this, which ties in the idea that since the soul would have glorified G-d in its deeds here it would itself be glorified in the end.
 This refers to the soul’s functions in the Afterlife. 0ASee our work on Derech Hashem (“The Way of G-d” 1:3:12) where we cited Luzzatto’s statement that “while in the body, the soul was associated with rank physicality and evil in the natural course of things, and couldn’t shake them off. It suffered as a consequence, and experienced dimming and darkening…. And any degree of perfection it attained in the performance of mitzvot in this world was suppressed and made to sit dormant in the soul’s inner-core. The soul becomes frustrated, if you will, as a consequence, since it can’t radiate the way it’s capable of doing…. But the soul’s sense of frustration and suppression is alleviated in the Soul World (i.e., in the Afterlife). For there, the soul can radiate freely and to the degree appropriate to it, in light of the mitzvot it performed in life. The soul thus regains in the Soul World what it lost in life, and it also thus better prepares itself for what it will ultimately do and was created to do — purify the body after the resurrection, when the two will be rejoined”.
 In his note (46*) R’ Shriki cites Ramchal’s statement in Tikkunim Chaddashim (28) to the effect that Torah study is especially beneficial to the soul’s status while in this world — but the type of study that focuses on the soul’s “comprehending its Source and delighting in It”. That’s to say that when the soul is allowed to dwell on its Source, as it will in the Afterlife and in the World to Come, it’s allowed a touch of that in the here and now.
 They were told, “You may eat freely from any tree of the Garden but the Tree of the Knowledge of Good and Evil …; for on the day you do eat from it, you (and all of mankind) will surely die (as a consequence)” (Genesis 2:16-17).
 See Derech Hashem 1:3.
 See the statement that certain “individuals (who were so righteous and sinless that they wouldn’t have been expected to die, nonetheless) died as a consequence of the advice the serpent (gave Eve that lead to her sin)” (Baba Battra 17a).
 See note 5 to chapter 2:1 above about the idea of the “remarriage” and “reuniting” of body and soul.
 In order to shed light on the chronology, here’s the process laid out: the soul experiences the Afterlife after death, it then returns to the body at the resurrection, and the two then join together in the World to Come.
 Recall that when Ramchal speaks of the soul re-entering the body with all the strength of “its” good deeds he’s of course referring to all the good deeds that the individual who “inhabited” that body had done. See note 5 to the previous chapter.
See Derech Hashem 1:3 for more on this (aside from the citations in notes 2 and 5 above).
Rabbi Yaakov Feldman has translated and commented upon “The Gates of Repentance”, “The Path of the Just”, and “The Duties of the Heart” (Jason Aronson Publishers). His works are available in bookstores and in various locations on the Web.