and being in readiness to avenge all disobedience, when your obedience shall be made full.

Being ready to give punishment to whatever is against his authority, after you have made it clear that you are completely under his control.

και ειμεθα ετοιμοι να εκδικησωμεν πασαν παρακοην, οταν γεινη πληρης η υπακοη σας.

And having in a readiness to revenge all disobedience, when your obedience is fulfilled.