The Law Is The Servant Of Grace

“The Law serves the promises of God in two ways. First, because it exposes sin: ‘For by the law is the knowledge of sin’ (Rom. 3:20). Secondly, because it reveals human infirmity, in the sense that man cannot avoid sin without grace which was not given by the Law. And just as these two things, namely, the knowledge of a disease and the infirmity of the patient is a great inducement to seek medical treatment, so the knowledge of sin and of one’s impotency lead us to seek Christ. Thus, therefore, is the Law the servant of grace, inasmuch as it affords a knowledge of sin and actual experience of one’s impotency.”

-St. Thomas Aquinas, Commentary on Galatians.