It’s important to know that the wrongful can only do harm for a limited time . As soon as they’ll have reached that limit they’ll be removed from the world. Our sages referred to this as their having “filled (their) measure (of guilt)” .
Thus, while they can succeed in wrongdoing until then that’s only so that they’d have the opportunity to  be undone. As our sages put it, “The doors are (always) opened for anyone who tries to defile himself” (Yoma 38b) . Once this limit is reached they’ll be undone, as G-d’s anger will have been roused, and some sort of catastrophe will come about that will be their undoing.
 Ramchal is clearly referring to the sort of thoroughly wrongful, indeed wicked, sort of person referred to in 2:3:4, since he speaks just below about that person’s complete destruction.
Along other lines, this sentence could also be read to mean that they can only do so much harm and no more. The point is that their reach is limited either because of their mortality of course, because one can only succeed for so long in everything, or most especially — and this is his underlying argument — because G-d will only allow for so much of it.
 See Sotah 9a. As Ramchal indicates in the text, this is alluded to in the verse that reads “they are (to be) crushed when (their) measure (of guilt) is filled” (Job 20:22).
See Da’at Tevunot 142 and Adir Bamarom pp. 329-330
Esoterically, this could also refer to the fact that the Yetzer Hara itself can only last so long in the universe before being undone. See Da’at Tevunot 40, 96 and Adir Bamarom Ibid.
 … first do teshuva, which is denied no one, or if they chose not to do that, then to…
 … to defile himself indeed.
The obverse of this is the statement there that “if someone comes to purify himself, he’s helped”, meaning to say that while one is always enabled to do wrong if he wants to, anyone who wants to do good will not only be enabled to — he’ll be helped along, too.
(c) 2016 Rabbi Yaakov Feldman
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