Understanding progress and improvement (Epictetus)

Question

So, I've started reading "Discourses" of Epictetus. I'm stuck at Chapter IV. I can't understand the part that I'm going to post below. I've highlighted the most difficult piece, if you don't want to read everything. Gives the general idea of what he's speaking though:

He who is making progress, having learned from philosophers that desire means the desire of good things, and aversion means aversion from bad things; having learned too that happiness and tranquillity are not attainable by man otherwise than by not failing to obtain what he desires, and not falling into that which he would avoid; such a man takes from himself desire altogether and defers it, and he employs his aversion and defers it, and he employs his aversion only on things which are dependent on his will. For if he attempts to avoid anything independent of his will, he knows that sometimes he will fall in with something he wishes to avoid, and he will be unhappy. Now if a virtue is progress towards each of these things. For it is always true that to whatever point the perfecting of anything leads us, progress is an approach towards this point.

How then do we admit that virtue is such as I have said, and yet seek progress in other things and make a display of it? What is the product of virtue? Tranquillity. Who then makes improvement? Is it he who ha read many books of Chrysippus? But does virtue consist in having understood Chrysippus? If this is so, progress is clearly nothing else than knowing a great deal of Chrysippus. But now we admit that virtue produces one thing, and we declare that approaching near to it is another thing, namely, progress or improvement. Such a person says one, is already able to read Chrysippus by himself. Indeed sir, you are making great progress.

Will you not show him the effect of virtue that he may learn where to look for improvement?

Seek it there, wretch, where your work lies. And where is your work? In desire and in aversion, that you may not be disappointed in your desire, and that you may not fall into that which you would avoid; in your pursuit and avoiding, that you commit no error; in assent and suspension of assent, that you be not deceived. The first things, and the most necessary, are those which I have named. But if with trembling and lamentation you seek not to fall into that which you avoid, tell me how you are improving.

The way I understand it's that you improve yourself by chasing your dreams and trying to avoid that, which can upset you, that which can make you fail. But if you'll try to avoid things because of your fear that you can fail, you won't improve.

My gut tells me there's more to it, and I've read it over and over again, but that's the most I've squeezed out of the text.

Answer 1

In a few words, the argument of the brief Discourse, I,4 : Of progress or improvement, is the following :

Progress (προκοπῆς, to improve) is not to be able to read the books of the philosophers (like the Stoic Chrysippus), but instead in following his precepts: to lean towards virtue.

If virtue is the goal of perfection, progress is sistematically approaching this goal.

We have to measure it (progress or improvement) not so much in the "theoretical" knowledge of what is teached in books, but in the "practical" application of the said knowledge into daily actions.

What actions ? First of all into the sphere of desire and aversion, according to the principle that:

happiness and tranquillity are not attainable by man otherwise than by not failing to obtain what he desires, and not falling into that which he would avoid.

An then into the spheres of pursuit and avoiding, to avoid error, and of assent and suspension of assent, in order not to be deceived.

The first is the most necessary, because

if you are in a state of fear or pain [trembling and lamentation: τρέμων καὶ πενθῶν] you will not be able to judge correctly and thus you will choose what is not good [falling into that which he would avoid].