1) The civil use. That is, the law serves the commonwealth or body politic as a force to restrain sin. (e.g. Romans 13:1ff.) Though our political/legal context is different from that of the theocracy of ancient Israel, the divine principles in all Mosaic legislation remain relevant as we define, debate and establish laws in our land today.
2) The pedagogical use. That is, the law also shows people their sin and points them to mercy and grace outside of themselves.
3) The normative use. 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.
Note: In this model, Christ appears as the end of the law, both in the sense that the pedegogical use leads to Christ as to a goal and in the sense that the normative use has become a possibility for man only because Christ has fulfilled the law in himself. In other words, in both the pedagogical use and the normative use Christ is central as the one who has saved his people from the law’s demands and the one who has merited the gift of Spirit-wrought obedience.
Thanks to the Reformed Reader Blog from which some of this material was borrowed.