The New Regimen of the Spirit
Paul introduces for the first time this expression in Romans chapter 7, as opposed to "the old regimen of the letter". The old regimen of the letter refers to the law, the commandments written in stone; on the other hand, the new regimen of the Spirit is of a New Covenant, in which the law is written in the heart and mind of man by the Holy Spirit.
The letter here, the same as in 2nd Corinthians 3, does not refer to human knowledge, human letters like it is sometimes interpreted but to the letter of the law of Moses. Or, which is the same, to all form of religion that has its norm outside of man, and prevails him.
It is that, the regimen of both covenants, the new and old, differ substantially in this. To obey the letter, is to take care of a huge amount of written commandments. To walk in the Spirit, on the other hand, is to follow the guidance that from the inside, from the heart, the Holy Spirit makes.
The Christian faith is a concern of the Spirit and not of the letter. It consist of living God's life, guided by the anointing that "teaches us concerning all things" (1st John 2:27), and not a concern of obeying a list of commandments. The imperative of this regimen works from the inside out; the other, from the outside in. The new regimen takes hold of God's life that is in the heart; the other, obtains his resources totally from man's will, because there is no Spirit inside.
Christianity is a living reality, not a doctrine that is imposed. The Old Covenant rests in laws, since it has no spirit. The new rests in the Spirit; therefore, there are no laws except that of Christ (1ª Cor. 9:21; Gál. 6:2), which is that of love (Rom. 13:10) and that of liberty (James 2:12). Christ living by the Spirit in the believer, lives a life of such quality that it does not require any type of law. There is no type of sin and is able to overcome any sin. It is the law of love, because love does not harm others and he who loves "bears all things, believes all things, hopes all things, endures all things". It is the law of freedom because the life of Christ does not require restrictions.
If there is something that may seem like laws to some, it is in reality suggestions, pleads, and demands done by the Spirit, no to man, but to God's life that is in the hearts of the believers. In the New Covenant it is not man who obeys laws-it has already been proven that man is incapable of obeying-but it is the power of grace working in the believer. A Christian, obedient to the Spirit for love and freedom, does not require any type of law. Everything that he does will be the expression of the new life he carries inside. A heavenly life, sweet, generous, powerful, and delicate. God's eternal life in Christ.