Assuring us that “wrong was created” from the first “to be undone” in the end, Ramchal nonetheless digresses a bit to look on the “bright” side of evil, if you will — to lay out all the beneficial and valuable things that will ultimately come of evil’s existence despite all its manifest harm — if we resist it, that is.
First off, evil and injustice will ultimately prove to be the bleak and wan polar opposite of all the goodness that will be manifest when G-d’s presence irradiates in the end. We’ll be able to see that for ourselves, we’ll realize just how mistaken and self-destructive it is to fall for evil’s charm, and we’ll chose goodness instead and be rewarded for that .
Secondly, our having been tempted by wrong and having resisted it — thus passing the great personal challenge that every human being faces again and again — will prove to be to our benefit in the end .
Thirdly, since our mission in life is to rectify all that has been broken in this world and to set back on track all that had been derailed, and given that that’s only possible with the existence of wrong and injustice which have everything go off, it follows then that our having the opportunity to resist wrong enables us to succeed in our mission and to serve as G-d’s “partners” in this universe, as Ramchal terms it. And it likewise follows that we’ll be rewarded for all that.
And finally, as every honest person will admit, our faith is often challenged — by the seeming random and haphazard way things work in this world; and by all the many instances of evil and injustice in the world despite all of G-d’s assurances to us that He Himself directs the world, that His eyes are always fixed on us and our situation, that He’s fair and trustworthy, and that the righteous will always succeed and be content. For don’t all sorts of things come our way that seem to thwart our faith in these things ? But Ramchal’s point here is that our standing fast in our faith in G-d’s ultimate beneficence and integrity despite all that will serve us so richly in the end .
The fact remains though that while mankind is clearly a major factor in the undoing of wrong and injustice (as well as a major benefactor from it), we can’t undo it on our own by any means.
 The question of course is just who will be able to see that? If we ourselves will, and will be able to grasp the implications of all that on our own, all well and good. But what of our ancestors who wouldn’t have had the advantage of that revelation?
In fact, what’s known as Knesset Yisrael — the collective spiritual Jewish Nation past, present, and future — will be accredited with having grasped that truth, given that “The entire Jewish Nation (throughout time) is interdependent” (Rosh Hashanah 29a). That’s to say that those present will experience it on the spot, and those who’d lived beforehand would be granted credit for having already grasped it in their lifetimes, since they will be in the realm in which past, present, and future co-exist.
 A couple of alternative versions of Da’at Tevunot point to two different sources to illustrate the moral challenges we face as well as the factors in that mix. One version cites Zohar 2:163a which offers the following. There once was a king who had an only son whom he loved very much, and whom he ordered not to not to associate with any untoward woman. The king wanted to test his son’s mettle and determine if he was capable of being a righteous leader when his time came. The son promised that he’d accede to his father’s wish. There happened to be an alluring prostitute outside of the king’s palace. It occurred to the king to find out there and then just how committed his son was to keeping his promise. The king called the prostitute over and ordered her to seduce his son, which she did.
Now, if the son were to reject her allures and keep his promise to his father, the king would be very proud of and pleased with his son, and the king would shower him with all sorts of gifts and honors. Who would have caused the king’s son to please his father so and to earn all that honor? The prostitute, the Zohar indicates. The point is that while the yetzer harah can certainly prove to be our downfall, it could also prove to bring out the best in us and thus be an invaluable ally.
The other source cited as a reference is Berachot 32a, where a somewhat analogous parable is offered. A certain man had a son whom he had bathed, anointed, given a lot of food and drink, and upon whom he’d had a (full) wallet placed, and whom he had had set off in front of a house of prostitution. The boy stumbled, and the Talmud asked, “How could the boy help but stumble?” with the implication that the boy had no choice for all intents and purposes. But Ramchal’s point in citing this parable seems to be much along the same lines as the Zohar statement (if it was Ramchal himself who chose it or a more cautious editor who may have been off-put by the seemingly “heroic” role that the yetzer harah had been granted in the Zohar parable). Had the young son mustered the wherewithal to resist the prostitute despite the temptations, then imagine how great his reward would have been!
 See our last two paragraphs of Ramchal’s Introduction where we tried to depict this dilemma; also see note 1 to 1:1 where we offer sources in Ramchal’s works that speak about this idea.
 See 1:7:3 where the rewards for our victories in this realm are discussed.
In point of fact, even the greatest among us have been tried by the suffering of the righteous. See Psalm 73 and the Book of Job as well as so many works of Jewish Thought for discussions on this vexing issue.
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.