Against vainglory — from an unexpected angle. The passage opens Book VIII's file of morning self-admonitions. The first argument "toward freedom from conceit" (πρὸς τὸ ἀκενόδοξον) sounds almost bitter: you can no longer have lived a whole life as a philosopher, the sage's repute is beyond you — "your station opposes it too" (ἡ ὑπόθεσις, the imperial office). Yet the very thing that bars the road to the fame of philosophy frees one from caring about it: if it is too late to play the part, drop "how you will seem" (τὸ τί δόξεις) and attend to the substance.
Where the good life is — by elimination and remainder. The classic Stoic argument from exclusion (cf. 7.55): the good is found "nowhere" (οὐδαμοῦ, a fourfold refrain) — not in syllogisms (even logic is not the end), not in wealth, fame, or enjoyment. One thing is left: "to do what TERMman's nature seeks." And that is reached only through doctrines (δόγματα) — the beliefs about TERMgood and TERMevil "from which the TERMimpulses (ὁρμαί) and acts" flow. The causal order: right teaching → right impulse → right deed.
The core — the sufficiency of virtue. The closing formula compresses DOGMAthe sufficiency of virtue: the good for a human being is only what makes him "just, temperate, brave, free" (δίκαιον, σώφρονα, ἀνδρεῖον, ἐλεύθερον — the four cardinal goods); evil, only the contrary. All else is indifferent. Strict terms by the word: ἀγαθόν, κακόν, φύσις, ὁρμαί (the nouns are in the text); but δίκαιον/σώφρονα/ἀνδρεῖον are adjectives, not the abstract δικαιοσύνη/σωφροσύνη/ἀνδρεία, so they are not carried into the term list. The governing discipline is desire (what to count as good), the sustaining one action (the acts that follow from the doctrines).