What is the primary purpose of the Ten Commandments?

The primary purpose of the Ten Commandments is to show us that we fall short of God's demands and that we need faith in Christ for salvation. The law is our school teacher designed to bring us to Christ. It exists so that we can finally understand the depths of our depravity. The law says to men “Do this and live,” but we have no power to do it. The laws reveal that we cannot obey it, but there is One who can completely keep all the Law. That one is Jesus Christ. While the law says “do this” the grace of God says “it is finished.” Believe on Jesus Christ and God will freely give you His righteousness.