We’ve learned that all wrong and injustice — all pure evil, all cynical wrongdoing, all disregard for goodness and righteousness, all selfishness and hatefulness — will be undone in the end, and that G-d’s presence will eventually be conspicuous and oh-so right there. But what’s a human to do in the in the interim; and what sort of system will serve society for the meanwhile?
Thus we learn that G-d established a system of justice after He’d set out the parameters of wrong and injustice. So it’s time now to lay out the details of that system and to explain the sorts of rewards and punishments that go along with it . This second “tract”, if you will, is the realm in which we live out our moral and religious lives right now and that determines our destiny — for the meanwhile .
Understand of course that G-d has no need for such a system Himself to be sure, and that He’s utterly unaffected by it. As it’s said, “If you sin, how does that affect him? … If you are righteous, what do you give Him?” (Job 35:6-7).
He simply instituted a system that we would need, with notions of right and wrong as well as appropriate reward and punishment, and that would grant us insight into what would help or harm us spiritually. For though G-d doesn’t need us to do anything per se; He simply wants our input and loves it when we’re advanced .
So G-d instituted the moral and spiritual system of right and wrong in which we struggle to better ourselves, our world, and our relationship to Him; where people occupy different spiritual planes, and where they’re exposed to various means of rectifying things and to all the other elements of that system.
But all that obviously called for the setting-up of a series of complex essentials like appropriate reward and punishment and the like. After all, there’d need to be a way to determine which reward is to be granted for which particular good act and what punishment each wrongful act deserves; which realm each reward or punishment is to play itself out, which is to say in the here-and-now or in the Afterlife; how close to or far from G-d each act is to bring its perpetrator; how to undo harm; how to repent for one’s own wrongdoing, or the sort of misfortune that anyone who doesn’t repent would have to bear be rectified; etc. All of that would be needed as long as wrong and injustice reign.
Nonetheless the point still remains that hidden within this system and moving at its own pace deep within and far in the background is the other system — the one that will eventually allow for G-d’s Yichud to hold full sway and to undo all wrong and injustice. The point is that we’d need to be aware of both of these fundamental systems if we’re to understand G-d’s plan for this universe.
 For Kabbalistic references see R’ Friedlander’s notes 304 and 306; R’ Goldblatt’s notes 8 and 21, as well as note 60 on p. 485 of his edition and notes 2-3 on p. 268 there; and R’ Shriki’s note 98.
 See 1:14-16 where we laid out G-d’s two modes of functioning in the world: openly and clandestinely. While those chapters focused on both modes by comparing and contrasting them, Ramchal is about to explicate the latter, when reward and punishment form the backdrop behind everything we experience before our eyes (as well as what lies deep in the background).
 The Midrash raises the following point. “What does G-d care whether someone slaughters an animal on precisely the right spot on the neck rather than another before eating it? Will slaughtering it on one spot benefit Him while doing it on another one harm Him? Does G-d truly care whether someone eats a non-kosher animal or a kosher one?… (The point of the matter is that) mitzvot were given to purify G-d’s creatures (and not for His sake)” (Midrash Tanchuma, Parshat Shemini).
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.