1. Now, in order to understand why body and soul were to be joined together in the first place at conception — as well as to understand why G-d didnt combine the two from the first, as He very well could have — it would help us to recall G-d’s ultimate aim in creating us .
And were reminded that we were created by an act of Divine beneficence whose aim was for us to be showered by G-ds Presence as a reward for all we’d have done in life to advance ourselves and our world . Its just ironic, though, that He granted us one vital element of our being — a body  — that’s simply incapable of advancing itself spiritually, since it’s so self-absorbed and in constant contact with unholiness, which then apparently stymies G-d’s plan.
So G-d granted us another vital element, the soul, which was hewn from the inchoate “stuff” just beneath G-d’s very Throne of Glory, and which is by its very makeup capable of purifying our body and making it holy. In fact, purifying our body is the soul’s major function on earth. As it itself requires no purification, since its already pure, as we ourselves affirm each and every day when we recite, “My L-rd! The soul you have granted me is (indeed) pure!” (Morning Prayers) .
Hence, the soul isn’t sent here to per fect itself, as many mistakenly believe, but rather to perfect (and purify) the body . And its the soul’s purifying of it that allows the body to indeed eventually bask in G-d’s Presence and fulfill its own raison dêtre, and to thus be of great ultimate importance .
Understand that what our dual makeup also implies is that the whole of us — body and soul — works in tandem. The body-part breathes, eats, etc., and interacts with the world and thus rectifies that world when it acts in accordance with G-d’s wishes regarding what it eats and the like; or it demeans it when it does the opposite.
The soul, on the other hand, can neither rectify nor demean on its own. It entirely depends on the body here on earth to get by and about. Yet without the soul, the body would be worthless in the end, since it will not have served its ultimate function of basking in G-d’s presence . Now, in order to understand why body and soul were to be joined together in the first place at conception — as well as to understand why G-d didnt combine the two from the first, as He very well could have — it would help us to recall G-d’s ultimate aim in creating us .
The point is that they each only manage to function fully when they join forces.
 Ramchal points to the fact that the whole idea of our being comprised of both a body and a soul addresses the theme hed cited early on (1:2:1) about what we lack and would need to accomplish, and our raison dêtre.
See R Shrikis salient points in his note 46 o n pp. 75-76.
 See 1:1.
 The “body” in this context includes one’s mind, personality, memories, and the like — not just one’s rank physicality (we only use the term body because Ramchal does, in keeping with the convention).
 This is a vitally important point that helps explain the soul’s place in this world. For as Ramchal underscored in The Path of the Just, “G- d … breathed into us a soul so exalted and distinguished– a soul greater than the angels themselves” that it’s manifestedly out of place in this world. For what it’s meant to do, in fact, is to ready the body for the place in the World to Come, which both will then enjoy.  and its other elements cited in note 2 above.
 It’s essential to realize that this ability that we can draw upon — the soul’s ability to purify the body — is actually a function of the “body”, i.e., the full physical self, when it consciously chooses to better itself through Torah and mitzvot (though see R Goldblatts note 22 which discusses the extent to which that helps).
 Our sages likened the relationship between body and soul to the one between a disabled man and a blind one who decided to join forces in order to accomplish a particular goal. They related that “A certain king once owned an exquisite orchard that contained splendid figs, and he appointed two watchmen: one who was disabled and another who was blind (which would assure the king that nothing would be taken behind his back — or so he thought …). But the disabled man said to the blind one, ‘I see beautiful figs in the orchard. (I have an idea 🙂 Place me on your shoulder, and together we’ll get them… So the disabled man rode atop the blind one” and they accomplished their goal.
The “blind” watchman is the body, we’re told, and the “disabled” one is the soul, since the soul can’t go anywhere without the body and the body is blinded by its lusts (Sanhedrin 91B).
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.