The condition and characteristic of an uninstructed person is this: he never expects from himself profit (advantage) nor harm, but from externals. The condition and characteristic of a philosopher is this: he expects all advantage and all harm from himself.
We start off with a nice clear contrast between the lay person and the Stoic, then look at what movement along the path from one to the other looks like.
The signs (marks) of one who is making progress are these: he censures no man, he praises no man, he blames no man, he accuses no man, he says nothing about himself as if he were somebody or knew something; when he is impeded at all or hindered, he blames himself: if a man praises him, he ridicules the praiser to himself: if a man censures him, he makes no defense: he goes about like weak persons, being careful not to move any of the things which are placed, before they are firmly fixed: he removes all desire from himself, and he transfers aversion to those things only of the things within our power which are contrary to nature: he employs a moderate movement toward everything: whether he is considered foolish or ignorant, he cares not: and in a word he watches himself as if he were an enemy and lying in ambush.
Lets reconstruct this into a simple list:
- don't talk about be behaviour of others
- don't talk about yourself in a positive light
- blame yourself for any that you dislike in your life
- ignore praise and criticism
- move carefully through the world
- desire nothing, abhor only things within your power to fix
As you study and practice Stoicism, you should see yourself attaining more of these behaviours.
The last line is great: he watches himself as if he were an enemy and lying in ambush. From a Stoic mindset, you are literally your worst, and only, enemy because you are the only one who can cause your defeat (that is, your failure to follow the Stoic path).
One of the subtle implications that follows from this passage, and one that's been covered earlier, is that Stoicism is hard work. Too often I think the critics of Stoicism mis-read the dichotomy of control as saying that people can simply make a choice to be happy. Far from it; Stoicism is a hard and continuous struggle with yourself.