I know I have been on a T.F. Torrance kick recently. I promise I’ll lay off after this one. But I thought this was pretty good, and straight to the point.
By active obedience is meant the positive fulfillment of God’s saving will in the whole life of Jesus in his sonship. From the very beginning to the very end, he maintained a perfect filial relation to the Father in which he yielded to him a life of utter love and faithfulness, and in which he received and laid hold of the love of the Father. This active obedience was therefore his own loving self-offering to the Father in our name and on our behalf, and also his own loving appropriation of the Father’s word and will in our name and on our behalf.
By passive obedience is meant the submission of Jesus Christ to the judgement of the Father upon the sin which he assumed in our humanity in order to bear it in our name and on our behalf. This is the passion he endured in the expiation of our sins, but it is also his willing acceptance of the divine verdict upon our humanity.
This distinction between the active and passive obedience of Christ has been emphasized in Reformed theology not in order to distinguish or separate them, but in order to insist that the whole course of Christ’s active obedience is absolutely integral to his work of reconciliation, and that atonement cannot be limited to his passive obedience, that is to his passive submission to the penalty for our sin inflicted upon him in his death…
This mutuality of Christ’s active and passive obedience is important for it means that in our justification we have imputed to us not only the passive righteousness of Christ in which, in suffering his death on the Cross, he satisfied and atoned for our sins, but the active righteousness of Christ in which he positively fulfilled the Father’s will in an obedient life.
In other words justification means not simply the non-imputation of our sins through the pardon of Christ, but positive sharing in his human righteousness. We are saved therefore not only by the death of Christ which he suffered for our sakes but by his vicarious life which he lived for our sakes.”
Torrance, Incarnation, 80-81.