Let us, for another thing, beware of despising the Law of the Ten Commandments. Let us not suppose for a moment that it is set aside by the Gospel, or that Christians have nothing to do with it. The coming of Christ did not alter the position of the Ten Commandments one hair's breadth. If anything, it exalted and raised their authority (Rom 3:31).
The Law of the Ten Commandments is God's eternal measure of right and wrong. By it is the knowledge of sin. By it, the Spirit shows men their need of Christ, and drives them to Him. To it, Christ refers His people as their rule and guide for holy living. In its right place it is just as important as the glorious Gospel. It cannot save us. We cannot be justified by it. But never, never let us despise it. It is a symptom of an ignorant and unhealthy state of religion, when the Law is lightly esteemed. The true Christian delights in the Law of God.
~ J. C. Ryle (Expository Thoughts on the Gospel of Matthew)