The order is aimed exactly where one has already given up. ἀπογινώσκω does not mean "to find difficult" but "to give up, to write off": it is a word of the courts and of medicine, used of a case abandoned and of a patient past hope. Marcus does not argue with the verdict, nor talk himself into thinking the thing feasible; he says, train yourself in these too (καὶ ὅσα). The despair stays where it is; only what one does with it changes.

The example is physiologically exact. A rider's left hand holds the bridle (χαλινός), the right being taken up with a weapon or a whip. So the left, good for nothing else, grips the rein ἐρρωμενέστερον — "more strongly," literally "with more force in it" — than the "strong" right. The argument is not that the weak thing is secretly strong, but that strength is a deposit left by practice, distributed according to what has been done, not according to what was given.

The passage stands on a single root. ἐθ- is run through three times and carries the whole thought: ἔθιζε (train) — ἀνέθιστον (want of habit) — εἴθισται (has been trained). Between the first word and the last the entire proof is contained: what is now called impossible differs from the possible by a number of repetitions.

Its place in the book. Two kindred counsels about acquired skill stand nearby: 12.9 (principles should be with you as the hand is with the pancratiast, not as the sword with the gladiator) and, at the other end of the corpus, 5.9, where one is told not to be disgusted at one's lapses but to "come back" to philosophy as a man with sore eyes comes back to the sponge and the egg. Cf. 7.61: living is more like wrestling than dancing — footing matters more than a rehearsed routine. The governing discipline is action, the sustaining one assent.