Among many other important points, Stephen J. Grabill, in his well-needed book, Rediscovering the Natural Law in Reformed Theological Ethics, makes clear Calvin’s support of the existence and knowability of natural law. One such text is from the Reformer’s commentary on that great Psalm ode to the law, Psalm 119:
[Psalm 119:]52.I called to mind thy judgments of old, O Jehovah! In this psalm, the judgments of God are generally taken for his statutes and decrees, that is, his righteousness. … In this place, in consequence of the qualifying phrase, of old, it is more probable that they refer to the examples by which God has made himself known as the righteous Judge of the world. Why does he say that the law of God has been from everlasting? This may to some extent be accounted for from the righteousness here mentioned not being of recent growth, but truly everlasting, because the written law is just an attestation of the law of nature, through means of which God recalls to our memory that which he has previously engraved on our hearts. [Grabill, 73]
The last phrase, of course, alludes to Romans 2:15 as it has been commonly interpreted, as a reference to the knowledge of right and wrong that God has provided to all people.
This element of Calvin’s teaching is very relevant for the current church, at least in my opinion. It shows that one of the biggest sources of the Reformed tradition was in continuity with the natural law tradition, and that Karl Barth and the Barthians have radically departed from the Reformed tradition on this matter. It also, hopefully, will make it easier for many who have great love for the Reformer to begin to appreciate the expansive and foundational natural law tradition, with its careful analysis of the human person and all the variegated moral situations he can find himself in. Perhaps, through that, the Reformed church might once again be able to reclaim their part in that ongoing project, a project which has untold riches of wisdom on many important contemporary issues, if only we would look.