Westminister Shorter Catechism 82

82. Question: Is any man able perfectly to keep the commandments of God?

Answer: No mere man, since the fall, is able in this life perfectly to keep the commandments of God, but doth daily break them in though, word, and deed.

Meditating on the Law of God (as we have) is a humbling exercise. Reflecting on the Law and all that it demands, forces our mouths shut before God. Who of among us has perfectly kept this Law? The demands of the Law, in its summarized form of the Ten Commandments, at first appearances may not seem too much to ask. Yet it’s upon careful self-examination that we come face to face with a heavy revelation. First, we encounter the standard of God’s righteousness and secondly our inability to meet the demands of the Law. 

The Law is known in our hearts in seed form but we are graciously given it in Scripture that we would have a more exact knowledge. Apart from the revelation of God, we (as sinners) think there is life. Yet it is when the Spirit speaks to our hearts through the Law that our eyes are opened and we see that we aren’t alive but dead. Through the Law the dead man is killed. (Romans 7:8-9) The Law makes us aware of our guilt and bondage to sin. The Law is like an x-ray that examines us in ways we never could on our own. It reveals to us that we are inadequate to satisfy its demands in even the basic capacity.

The Law and Gospel while different are not contrary. The essence of the Law communicates to us the standard of God’s righteousness and what is required of us for eternal life. The difference is how they instruct us to obtain this righteousness. The Law forces us to move and we will either move more inward trying to fulfill the demands of the Law on our own. Or we will fly to the only remedy that is pronounced in the Gospel, Jesus. (Col 2: 13-14) By faith we receive the righteousness of God that is in Jesus. The Law also tells us that the standards of God’s righteousness does not change based on our ability to meet them. Therefore the Law only tells us what we must do, with no regard to our ability to do it. (Gal 3:12) Living under the Gospel, Christians find comfort in this, that a spirit wrought union with the risen Christ by faith makes his righteousness ours. The Law no longer condemns us but confirms us because we have a righteousness that is not our own.

In essence, we see the similarity between the Law and the Gospel, the righteousness of God. But we also see the differences between them. The Law tells us “Do this and live”. The Gospel tells us “This has been done for you by Jesus”.