If, as Paul say, the law is not faith (Gal. 3.11-12), the one excludes the other. So the law is quite different from faith. And so justification is by faith alone.

Calvin is sensitive to language, particular over the question of the appropriateness of using non-scriptural terms, or terms in explication of Scriptural doctrine. He disdains the use of 'merit', as we have noted. But he defends the phrase 'justification by faith alone' even though the 'by alone' is not found verbatim in Scripture. The addition is legitimate because it captures Paul's thought. If faith excludes works and justification is by faith, then justification is by faith alone.

He next tackles another 'subterfuge', that the works in question are ceremonial Jewish works and not the observance of the moral law. And so moral observance is necessary for justification. But Paul is clear. (Ga.3.10)