In The True Method of Giving Peace to Christendom and Reforming the Church John Calvin helps bring clarity to one of the issues he and many of the other reformers had with the Adultero-German Interim, namely the source of our righteousness. What a helpful reminder to all Christendom (emphasis mine):
On the whole, let us remember that the debate here is not simply concerning the manifold grace of God toward us, but concerning the cause of our Reconciliation with him. This cause, unless it is fixed as one, is null. For Scripture does not tell us to borrow only part of our righteousness from Christ in order to supply what is wanting in our works; but the Apostle plainly declares that Christ himself was made righteousness to us. And in another passage he declares, that men are righteous before God by the very circumstance that our sins are no longer imputed to us. (1 Cor. 1:30; 2 Cor. 5:19.)
Do you ever “borrow only part” of the righteousness that comes through Christ and try to make up the rest on your own? Those are troubled waters my friend. Beware. Calvin continues:
In order that ambiguities may be removed, it is necessary that the Righteousness which we obtain by faith, and which is freely bestowed upon us, should be placed in the highest rank, so that, as often as the conscience is brought before the tribunal of God, it alone may shine forth. In this way the righteousness of works, to whatever extent it may exist in us, being reduced to its own place, will never come, as it were, into conflict with the other; and certainly it is just, that as righteousness of works depends on righteousness of faith, it should be made subordinate to it, so as to leave the latter in full possession of the salvation of man. There can be no doubt that Paul, when he treats of the Justification of man, confines himself to the one point—how man may ascertain that God is propitious to him? Here he does not remind us of a quality infused into us; on the contrary, making no mention of works, he tells us that righteousness must be sought without us; otherwise that certainty of faith, which he everywhere so strongly urges, could never stand; still less could there be ground for the contrast between the righteousness of faith and works which he draws in the tenth chapter to the Romans. Wherefore, unless we choose to sport with so serious a matter, (this would be fraught with danger!) we must retain propriety of expression, which carries with it the knowledge of the thing expressed. Were the thing conceded to us by those who entangle this part of the doctrine by their comments, I would easily give up all contest about the word. But those who confound the two kinds of righteousness together, seeing the thing they aim at is to prevent the righteousness of Christ from being entirely gratuitous, are on no account to be borne.
John Calvin and Hendry Beveridge, Tracts Relating to the Reformation, Volume 3 (Bellingham, WA: Logos Research Systems, Inc., 2009), 246-47.