Grace enables our Godly fear, which empowers obedience (Deuteronomy 10:12-17). Law alone hardens the heart unless and until it is softened by Christ, Who lifts the veil from a hard heart. Emphasis and dependence upon Law alone to make us obedient will fail.. Approached in this way, it will only "veil" our hearts, and harden us to the Spirit of Christ.
From Paul we can see that there seemed to be both approaches in the church at Corinth when he wrote his second letter to them. Hence the cause for his terminology and tone in 2 Corinthians 3:5-18. There were orthodox Jews, and Gentiles in this church. So it is logical that both concepts existed together. He makes very strong statements concerning the approach of the Jewish element. The Apostle Paul makes it very clear that to them he was the messenger of Christ for a new covenant, which dispensed a glory that would never pass away, unlike the glory on Moses’ face, which was fading away. This glory was hidden from them, although it was fading at the same time. Only the glory that Christ brings to the Law will never fade.
The glory in the face of Moses was fading because the "administration of death" is what the Law brings forth. Israel proved for all the world to see in the wilderness and before, that the Law could not be kept perfectly and consistently. But perfection and consistency is what the Law required. Paul ministered the administration of the Spirit through Christ - not the letter, which kills. It kills because the penalty for sin is death, and there is no human without sin (Romans 8:20-23). Until this day the rejection by the orthodox Jews causes the veil to remain. If they would accept Christ, then the Spirit of Christ would remove the veil of unbelief, and they would come to understand the new covenant. The new administration of the Spirit, and not administration of the Law alone.
It is important to remember that the administration of the Spirit does not do away with the Law. Rather, it involves a different way to accomplish the same purpose, which is righteousness. Recall the words of Jesus when He affirmed that He has not come to destroy the Law, but to "fulfill" it. This the administration of the Spirit will now do. Paul in his letter to the Romans, makes clear that our faith in Jesus Christ does not do away with the Law. On the contrary, faith establishes and upholds the Law. How? Because in Christ we are considered to be righteous through faith in Him, until we are perfected. When perfected, we will be in complete harmony with the Law of God. Therefore, in every way, faith upholds the Law. It was not God’s Law that was faulty, which some have mistakenly believed, and thought that Christ’s death has done away with the Law. A clarification of Jeremiah 31 by the writer of Hebrews helps us to understand the position of the Law:
“For if that first covenant had been without defect, there would have been no room for another one or an attempt to institute another one. However, He finds fault with them [showing its inadequacy] when He says, Behold, the days will come, says the Lord, when I will make and ratify a new covenant or agreement with the house of Israel and with the house of Judah.” (Hebrews 8:8 AmpBible)
The flaw was not with God’s Law, but with the ability of Israel to keep it. This is very important to understand, in all instances of references to God’s Law.
Now we can see how that the grace of God in Christ administers obedience by and through the Spirit of Christ. The Law itself is "spiritual" (Romans 7:14), and is the reason it cannot be kept through the flesh alone. The Law shows us what sin is, and is an umpire in our lives, witnessing our efforts to be obedient. Before faith in Christ, we were condemned by it, simply because we could keep it perfectly. We now have the desire to obey, but with many failures But now, we can grow in successes instead of failures. Now, our heart's desire is to obey by the Spirit's empowerment, from a sincere and pure heart.
Desiring now, by the grace of Christ our purpose is not to sin. However, we still do. It was the same with Paul:
"For I endorse and delight in the Law of God in my inmost self [with my new nature]. But I discern in my bodily members in the sensitive appetites and wills of the flesh] a different law (rule of action) at war against the law of my mind (my reason) and making me a prisoner to the law of sin that dwells in my bodily organs in the sensitive appetites and wills of the flesh]. O unhappy and pitiable and wretched man that I am! Who will release and deliver me from [the shackles of] this body of death? O thank God! [He will!] through Jesus Christ (the Anointed One) our Lord! So then indeed I, of myself with the mind and heart, serve the Law of God, but with the flesh the law of sin." - Romans 7:21-25 (Amplified Bible)
Notice it is Jesus Christ Who will deliver us from the death sin would bring, which is strengthened by the Law: “O death, where is your victory? O death, where is your sting? Now sin is the sting of death, and sin exercises its power upon the soul] through the abuse of] the Law. But thanks be to God, Who gives us the victory [making us conquerors] through our Lord Jesus Christ.” (1 Corinthians 15:55-57 AmpBible)
Finally, the work of grace through Christ will have brought to fruition the obedience to God what the Law alone could not do. The new covenant in Christ will encompass all of Israel nationally, and bind Israel and Gentiles alike into one family (Galatians 6:15-16). God’s spiritual children will then have His Law, and His nature, written into their hearts - permanently.
The Family and Kingdom of God.
“For this is the covenant that I will make with the house of Israel after those days, says the Lord: I will imprint My laws upon their minds, even upon their innermost thoughts and understanding, and engrave them upon their hearts; and I will be their God, and they shall be My people. And it will nevermore be necessary for each one to teach his neighbor and his fellow citizen or each one his brother, saying, Know (perceive, have knowledge of, and get acquainted by experience with) the Lord, for all will know Me, from the smallest to the greatest of them. For I will be merciful and gracious toward their sins and I will remember their deeds of unrighteousness no more. When God speaks of a new [covenant or agreement], He makes the first one obsolete (out of use). And what is obsolete (out of use and annulled because of age) is ripe for disappearance and to be dispensed with altogether.” - Hebrews 8:10-13 (Amplified Bible)