5. HOW DOES THE SATISFACTION OF CHRIST BECOME OUR RIGHTEOUSNESS, SEEING THAT IT IS OUTSIDE OF US?
At first view it seems absurd that we should be justified by any thing without us, or by something that belongs to another. It is necessary, therefore, that we should explain more fully how the satisfaction, or obedience of Christ becomes ours; for unless it be made ours, or be applied unto us, we cannot be justified by it, just as little as a wall can be white, if whiteness be not applied, or fixed upon it. We remark, then, that there are two ways in which the satisfaction of Christ is made over unto us:
1. God himself applies it unto us, that is, he makes the righteousness of Christ over unto us, and accepts of us as righteous on account of it, as if it were ours.
2. We apply it also unto ourselves when we receive the righteousness of Christ through faith, that is, we rest assured that God will grant it unto us, that he will regard us as righteous on account of it, and that he will free us from all guilt.
There is, therefore, a double application; one in respect to God, and another in respect to us. The former is the imputation of Christ’s righteousness, when God accepts of that righteousness which Christ wrought out, that it might avail in our behalf, and accounts us as righteous in view of it, as much so as if we had never sinned, or had at least fully satisfied for our sins. The other side of this application which has respect to us, is the act itself of believing, in which we are fully persuaded that it is imputed and given unto us. Both sides of this application must necessarily concur in our justification; for God applies the righteousness of Christ unto us upon the condition, that we also apply the same unto ourselves by faith. For although any one were to offer another a benefit, yet if he to whom it is offered does not accept of it, it is not applied unto him, and so does not become his. Hence without this last application the former is of no account. And yet our application of the righteousness of Christ is from God; for he first imputes it unto us, and then works faith in us, by which we apply unto ourselves that which is imputed; from which it appears that the application of God precedes that which we make, (which is of faith) and is the cause of it, although it is not without ours, as Christ says, “You have not chosen me, but I have chosen you.” (John 15:16)
Heidelberg Commentary, pp. 590-591 - Ursinus