This distinction is often called tripartite division of the law.
I ran across this series of blog posts:
- http://maelandcindy.blogspot.com/2008/06/is-mosaic-law-tripartite.html
- http://maelandcindy.blogspot.com/2008/06/is-mosaic-law-tripartite-historical.html
- http://maelandcindy.blogspot.com/2008/07/is-mosaic-law-tripartite-analyzing.html
- http://maelandcindy.blogspot.com/2008/07/is-mosaic-law-tripartite-analyzing_19.html
- http://maelandcindy.blogspot.com/2008/07/is-mosaic-law-tripartite-wrapping-up.html
- http://maelandcindy.blogspot.com/2008/08/is-mosaic-law-tripartite-entertain.html
- http://maelandcindy.blogspot.com/2008/08/is-mosaic-law-tripartite-some-final.html
which considers the division of the law into "moral", "civil", and "ceremonial" parts. The Westminster standards (and others), even go on to claim that the "moral" law is one and the same with the Ten Commandments. This sometimes becomes something of a hermeneutical key, e.g., when interpreting passages that point out that the law is overturned, asserting that the passage is referring to the ceremonial law.
That said, Confessional Presbyterians and Reformed Baptists are not typically considered Thomists, and yet find this principle as no minor point in their confessional documents. Aquinas's reasoning is usually rejected when directly addressed, but the essential division is held nonetheless. Is there some other supporting reasoning, or an alternative origin other than via Aquinas? Likewise, is there support for equating the "moral law" (which is said to remain on Christians) with the Decalogue?

