The Three Uses of the Law
1) The civil use (usus politicus sive civilis). That is, the law serves the commonwealth or body politic as a force to restrain sin. This falls under the general revelation (revelatio generalis) discussion in most of the scholastics as well as natural law (cf. Rom 1-2).
2) The pedagogical use (usus elenchticus sive paedagogicus). That is, the law also shows people their sin and points them to mercy and grace outside of themselves. In Muller’s summary, this is “the use of the law for the confrontation and refutation of sin and for the purpose of pointing the way to Christ” (p. 320). This can be found in the Heidelberg Catechism Lord’s Days 2-4.
3) The normative use (usus didacticus sive normativus). That is, this use of the law is for those who trust in Christ and have been saved through faith apart from works. It “acts as a norm of conduct, freely accepted by those in whom the grace of God works the good” (p. 321). This can be found in the Heidelberg Catechism Lord’s Days 32-52.