Jamieson, Fausset and Brown on 2 Corinthians 10:6

6. Translate, "Having ourselves (that is, being) in readiness to exact punishment for all disobedience," &c. We have this in store for the disobedient: it will be brought into action in due time.

when your obedience, &c.--He charitably assumes that most of the Corinthian Church will act obediently; therefore he says "YOUR obedience." But perhaps some will act otherwise; in order, therefore, to give all an opportunity of joining the obedient, he will not prematurely exact punishment, but wait until the full number of those gathered out to Christ has been "completed," and the remainder have been proved incorrigible. He had acted already so at Corinth (Ac 18:6-11; compare Ex 32:34; Mt 13:28-30).