Being in readiness (εν ετοιμω εχοντες). This very idiom occurs in Polybius, Philo, etc. "Holding in readiness." In 2. Corinthians 12:14 we have ετοιμως εχω for the same idea (adverb ετοιμως).

Disobedience (παρακοην). Rare word (Plato, papyri) hearing amiss (aside), failing to hear, refusing to heed (cf. Matthew 18:17 for same idea in παρακουω). In N.T. only here; Romans 5:19; Hebrews 2:2. In contrast with υπακοη (obedience) rather than the common απειθια (Romans 11:30; Romans 11:32).

When your obedience shall be fulfilled (οταν πληρωθη υμων η υπακοη). Indefinite temporal clause with οταν and first aorist passive subjunctive. Paul expects that the whole church will become obedient to Christ's will soon as came true.