But before faith came, we were kept under the law, shut up unto the faith which should afterwards be revealed. Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith. But after that faith is come, we are no longer under a schoolmaster. (Galatians 3:23-25).

Schoolmaster = Paiadagogos = a guardian, or guide, of boys. A trustworthy slave who was charged with supervising the life and morals of the son of a well-to-do family. The boy was not allowed to step out of the house without him before arriving at the age of manhood.

The Law and the Prophets point us to Christ, but they do not teach us how to be a Christian. The Law and the Prophets can keep us out of trouble until we come to Christ. The Old Testament still has this value of revealing the futility of trying to live a godly life by our own efforts and thus pointing us to our need of Christ. But Christ is the true teacher who empowers us to live his teachings.