Saturdays with Calvin #68

Justification, moreover, we thus define: The sinner being admitted into communion with Christ is, for his sake, reconciled to God; when purged by his blood he obtains the remission of sins, and clothed with righteousness, just as if it were his own, stands secure before the judgment-seat of heaven. Forgiveness of sins being previously given, the good works which follow have a value different from their merit, because whatever is imperfect in them is covered by the perfection of Christ, and all their blemishes and pollutions are wiped away by his purity, so as never to come under the cognizance of the divine tribunal. The guilt of all transgressions, by which men are prevented from offering God an acceptable service, being thus effaced, and the imperfection which is wont to sully even good works being buried, the good works which are done by believers are deemed righteous, or; which is the same thing, are imputed for righteousness.

Institutes of the Christian Religion 3.17.8 John Calvin, translated by Henry Beveridge, Hendrickson, pg, 533.