The phrase “law of faith” is a phrase used by Paul the apostle in Romans 3:27 as a figure of speech in contrast to the law of works. by seeing what Paul was saying regarding the Mosaic law, we can contrast it with a lot of faith. We know this is permissible because Paul repeatedly contrasts them in many scriptures. Let’s look at the immediate context of Rom. 3:27.

Romans 3:27, “Where then is boasting? It is excluded. By what kind of law? Of works? No, but by a law of faith.”

Paul had spoken of the Old Testament “law and the prophets,” (Rom. 3:21). He then spoke of righteousness through faith (v. 22), that all have sinned (v. 23), that we are justified by grace in Christ (v. 24), whom God displayed as a propitiation (v. 25), and that God is a justifier of those who have faith in Christ (v. 26).  We then get to verse 27, the one under examination, where he contrasts the law of works with law of faith.  He then goes on to say that we are justified by faith apart from works of the law (v. 28), that God is the God of Jews and Gentiles (v. 29), who justifies the circumcised and uncircumcised (v. 30), and that the law is established by faith, not nullified (v. 31).

So, it would seem that Paul is speaking about this law in a figurative way in order to teach that justification is by faith, not the works of the law. This “law of faith” would mean that we are saved by faith in Christ alone. Please consider the following quotes from commentaries on this topic.

“See he calls the faith also a law, delighting to keep to the names, and so allay the seeming novelty. But what is the “law of faith?” It is, being saved by grace. Here he shows God’s power, in that He has not only saved, but has even justified, and led them to boasting, and this too without needing works, but looking for faith only.” Schaff, Philip, ed. Saint Chrysostom: Homilies on the Acts of the Apostles and the Epistle to the Romans. Vol. 11…New York: Christian Literature Company, 1889.

Thus the “law of faith” would mean that the law is finally fulfilled in Christian faith. But it is slightly better to see a play on words here, so that the “law of works” is indeed the law of Moses but the “law of faith” refers to “the principle of faith.” Osborne, Grant R. Romans. The IVP New Testament Commentary Series. Downers Grove, IL: InterVarsity Press, 2004.

But the principle of the law of faith, which has been shown to be the only one available for the justification of either Jew or Gentile.” “Spence-Jones, H. D. M., ed. The Pulpit Commentary: Romans. The Pulpit Commentary. London; New York: Funk & Wagnalls Company, 1909