Necessity of Works?

Who wrote this? ” opera sunt necessaria ad salutem, sed non causant salutem, quia fides sola dat vitam ” (works are necessary to salvation, yet they do not cause salvation, for faith alone gives life).

Norman Shepherd would be a good guess, except that he doesn’t write in Latin.

Calvin would be a good guess too. But wrong.

It’s that Law-Gospel fanatic, Luther.