Two guarantees. The passage joins the two supports of Stoic tranquility in a single symmetry — "one's own nature" and "the common nature." The governing discipline is desire (acceptance of what happens); the sustaining one is assent (inner freedom).
(1) No one will hinder. "DOGMATo live by the reason of your own nature (κατὰ τὸν TERMλόγον τῆς σῆς TERMφύσεως), no one (οὐδείς) will hinder you." Virtue lies in inner action, and that no external force can take away: the freedom of a rational being is inalienable (cf. 06-52: judgment is in my power). (2) Nothing will happen against the Whole. "Contrary to the reason of the DOGMAcommon nature (κοινὴ φύσις), nothing (οὐδέν) will befall you." All that happens is by the single Logos of the Whole; so nothing "contrary to nature," and therefore nothing truly evil, will come to you.
A double irrevocability. The two "nots" (οὐδείς / οὐδέν) form a defence: from within, my rational life is shielded from other people; from without, the very course of events is shielded by the rationality of the cosmos. Between these two guarantees there is no room left for fear or complaint.
Parallels. DOGMALiving according to nature (one's own and the common) — 05-25 (κοινὴ / ἐμὴ φύσις); 06-09 (all is by the nature of the Whole); the TERMlogos as the bond of personal and cosmic nature; the inalienability of inner freedom — 06-52; Med. 5.34; 8.7; 11.1.