Galatians 3:23-25

Before this faith came, we were held prisoners by the law, locked up until faith should be revealed.

(v23, NIV)

Before faith, we were held captive to the law. As prisoners, we were forced into submission underneath the law. There was nothing else, only the law. Abraham lived by faith, and so it was counted to him as righteousness. However, this faith being revealed is the faith in Jesus. This is the saving faith.

So the law was put in charge to lead us to Christ that we might be justified by faith.

(v24, NIV)

What was the purpose of the law? It leads us to Christ. Through our failed attempts at following the law, we realize that we cannot do it. It goes to show us that there has to be another way and we cannot do it by ourselves.

Now that faith has come, we are no longer under the supervision of the law.

(v25, NIV)

This faith through Jesus saves us. As we are prisoners to the law, it saves us as the freeing of a prisoner. If we were never enslaved, we wouldn't desire to be free. Thus, being imprisoned shows us our need to be free. This is all leading us Christ.