01
The idea
Courage in the Stoic sense is not primarily physical. It is the willingness to act well when acting well costs you something — standing, money, comfort, a relationship, the good opinion of a room. Most of the courage an adult life demands is exercised in conversations rather than in danger.
Temperance is proportion: knowing where the line is and stopping at it. It governs appetite, but far more importantly it governs response — the second email, the extra sentence, the retaliation that was warranted and still should not have been sent.
The pair is deliberately opposed. Courage says go; temperance says this far. A person with only the first becomes reckless and calls it conviction; a person with only the second becomes careful and calls it wisdom. The virtues are meant to be run together, which is why the Stoics treated them as aspects of one knowledge rather than four separate skills.
02
Why this matters
Nearly every regret an honest person can name falls into one of two categories: something they did not say, and something they said too much of. That is a courage failure and a temperance failure, and the two account for most of the field.
Courage is also the virtue that converts insight into anything. Everything up to here produces clarity, and clarity that is not acted on is a more sophisticated form of paralysis.
Temperance is what stops the philosophy from being used to justify excess. Everything in this tradition can be run too hard — the discipline, the austerity, the self-examination — and there is no internal brake except this virtue.