Paul tells us in Romans 7:14 that the law is spiritual. But what does that mean? And why does it matter? I’d like to make a few suggestions regarding the nature and the importance of the law’s spirituality.
In Romans 7 Paul is arguing that believers are dead to the law by the sacrifice of Christ (7:4). However, Paul shows us that without a true understanding of the law, a spiritual understanding, we remain deceived about our standing with the law. For example, Paul had thought that he was “alive” (7:9). In fact, elsewhere he tells us that he was blameless according to the law (Phil 3:6). But, when the Holy Spirit opened Paul’s eyes to his true standing before the law, the law killed him.
1. The spirituality of the law shows us that mere outward obedience can never fulfill God’s requirements.
“The law which proceeds from the Holy Spirit of God, demands not only the obedience of external conduct, but the internal obedience of the heart. If Paul had still regarded the law as a rule extending merely to his outward conduct, he might, as formerly, when he strictly adhered to its letter, have continued to suppose himself just and good.”
Paul’s outward conformity to the law would have merited the blessings of a non-spiritual law. However, because the law is spiritual, the motives and intentions of the heart become damning evidence against anyone who seeks to justify themselves.
2. The spirituality of the law exposes the magnitude of our sins.
If God’s law condemns us all based on our outward sins alone, how much more does our condemnation grow if we include the list of our internal sins as well? Calvin affirms:
“If we are convicted as rebels against God because of external, visible acts, let us remember that God will find an infinite number, indeed, an abyss of evil desires writhing inside of us, though they are not regarded by men as rendering us guilty. We must, therefore, conclude that in everything and in every way we are drowned in perdition, until God looks in pity upon us, and draws us out.”
The spirituality of God’s law leaves us exposed. We have nowhere to hide from the truth of our condemnation. However, God did not leave us without hope. In fact, the hope he provides for us shines all the brighter when we consider the spirituality of the law.
3. The spiritually of the law reveals the great virtue of our Redeemer.
The spiritual nature of the law magnifies Christ because we know that he didn’t merely keep the outward form of the law. While it is true that Jesus never stole, murdered, took the Lord’s name in vain, ect., we can also admire the holiness of our redeemer because he perfectly kept the law internally too. That means not only was he never a theif, but he was also perfectly generous. Not only was he never a murderer, but he also never hated anyone in his heart.
When he know that our substitute was perfect outwardly and inwardly, we can be assured that we too can stand forgiven of our inward sin. The spirituality of the law is the reason that we can approach the throne of God boldly, because our confidence lies in Christ’s perfect obedience to the law—both inwardly and outwardly.
 Robert Haldane, Romans, Geneva Series of Commentaries (Carlilse, PA. Banner of Truth: 1996), 291. See also: John Bunyan, “The Doctrine of the Law and Grace Unfolded,” https://books.google.com/books?id=yvhhAAAAcAAJ&pg=PA146&lpg=PA146&dq=spirituality+of+the+law&source=bl&ots=7rFq_3cnbd&sig=nVKxxvOdLibPMSkTooULOWiACps&hl=en&sa=X&ved=0ahUKEwjMyfv6jbnJAhWBPiYKHdqYCsE4ChDoAQgsMAU#v=onepage&q=spirituality%20of%20the%20law&f=false .
 John Calvin’s sermon on Galatians 5:19-23: http://www.the-highway.com/Calvin_Gal5b.html