Now the wet paint principle of the law might take effect, if I begin to think that I am justified by the law. If I base my salvation on my performance rather than on the finished work of Christ on the Cross, then sin will take advantage of the law and I will sin in that thing wherein I base my salvation on my own obedience.
Scripture teaches that we are saved by God's grace + works and it is not exclusively one or the other alone (We are saved by God's grace: Ephesians 2:8-9, Titus 3:5. We are saved by works: Matthew 19:17, James 2:17-18, James 2:24, Titus 1:16, Hebrews 12:14).
For example: 1 John 1:7 says that the blood of Jesus Christ cleanses of all sin if we walk in the light. If you were to compare 1 John 1:6-7 you will see similar wording used in 1 John 2:3-4. The words "walk in the light as He is in the light" is another way of saying "keeping God's commandment" and the word "darkness" is in reference to "not keeping his commandments" or "hating your brother."
6 "If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth:
7 But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin."
(1 John 1:6-7).
3 "And hereby we do know that we know him, if we keep his commandments.
4 He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him."
(1 John 2:3-4).
(a) If we say we have fellowship with him and walk in darkness (1:6) = He that saith, I know him, and keepeth not his commandments (2:4).
(b) We lie, and do not the truth (1:6) = is a liar, and the truth is not in him (2:4).
(c) If we walk in the light, as he [Christ] is in the light, we have fellowship with another, (1:7) = Hereby we do know that we know him, if we keep his commandments.
Anyways, I know what passage the author is referring to here. The author more than likely believes that Paul is talking about his struggle with sin as a Christian (See Romans 7:14-24). However, Paul is actually talking as a Pharisee (Before he became a Christian) who tried to obey a distorted version of God's laws that did not include Jesus or God's grace. The Pharisee religion was all about law and it did not include a Savior or His loving grace of forgiveness. So yes, it is true, if one seeks to follow a salvation system that is only works alone without God's grace, then one will always struggle in trying to keep God's laws. For one needs to get forgiven by God's grace and then the Lord will help the believer from there to obey God's commands.
In Romans 7:6, Paul says we should serve in newness of the spirit and not the oldness of the letter (Which is the Old Law and not the New Testament Scriptures that were still being formed). We are told to SERVE. How do we serve? Do we just do our own thing? No. We follow God's commands in the New Testament. This talk of the Old Law is the context of verses 14-24.
We are dead to the Law by the body of Jesus Christ (Romans 7:4). Would this be the Old Law or ALL law? 1 John 3:23 is a commandment that says we are to believe on the Lord Jesus Christ. This is a New Covenant Law. So obviously we are not dead to this Law or Command. The Scriptures also say, "but now commandeth all men everywhere to repent." (Acts of the Apostles 17:30). Are we dead to this Law? Surely not. Jesus said "repent or perish." (Luke 13:3). Peter told Simon to repent (by way of prayer to God) of his wickedness of trying to pay for the gifts of the Holy Spirit so that he may be forgiven (Acts of the Apostles 8:22). Sin is merely transgression of the Law (1 John 3:4). All this lets us know that men of God can break God's laws and they can be separated from GOD because of it. So surely some kind of Law of God is still in effect and has dire consequences for any person's soul who commits them. For Jesus said that if we do not forgive, we will not be forgiven by the Father (Matthew 6:15). If Jesus was talking to unbelievers, this would not make any sense. They would first need to accept Christ. So the only logical conclusion is that Jesus is talking to believers in Matthew 6:15. You do not forgive (i.e. you sin or break this law of God) and you will not be forgiven or saved. 1 John 3:15 says if you hate your brother you are like a murderer and no murderer has eternal life abiding in them. Again, you hate your brother (which can be a one time act) and you do not have eternal life. It's that simple. Also, Paul condemns circumcision several times. Galatians 5:2 is the biggest verse that condemns circumcision salvationism. Circumcision is an Old Covenant Law and it is not a New Covenant Law. Paul uses the word "law" when he speaks against circumcision. So we have to conclude that Paul is saying we are dead to the Old Covenant Law and not all Law. So again, this talk of the Old Law plays into verses 14-24.
In addition, Romans 8:3-4 says,
3 "For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh:
4 That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit." (Romans 8:3-4).
So which Law did God send His Son for so as to condemn sin in the flesh?
It was the Old Covenant Law.
For when Jesus died on the cross, the temple veil was ripped from top to bottom letting us know that the Old Testament laws were no longer valid because the Old Laws on the animal sacrifices and the priesthood were no longer acceptable.
Jesus Christ was now our Passover Lamb.
Jesus Christ was soon be our Heavenly High Priest (after He ascended to His father after His resurrection 3 days later) so He can be our mediator between God the Father and man.
Romans 8:4 says, "That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit."
This is saying that the righteous part or aspect of the Old Law can be fulfilled in us.
Paul says elsewhere,
8 "Owe no man any thing, but to love one another: for he that loveth another hath fulfilled the law.
9 For this, Thou shalt not commit adultery, Thou shalt not kill, Thou shalt not steal, Thou shalt not bear false witness, Thou shalt not covet; and if there be any other commandment, it is briefly comprehended in this saying, namely, Thou shalt love thy neighbour as thyself.
10 Love worketh no ill to his neighbour: therefore love is the fulfilling of the law."
(Romans 13:8-10).
So loving your neighbor is the righteousness of the Old Law!
We fulfill this law by walking after the Spirit and not after the flesh (i.e. sin).
So we see a consistent theme here. The word "law" used in general (with no actual description attached to it) is in reference to the Old Law in Romans 7 and Romans 8. This helps us to understand that Paul is telling us his past experience or life as a Pharisee in struggling to keep the Old Law unsuccessfully because he did not have Jesus Christ yet (in verses 14-24).
Furthermore, in Romans 8:2, we see the mention of how there are TWO laws. We also learn from this verse that keeping one of these Laws helps us to be set FREE from the other one.
In Romans 8:2, we see:
Law #1. - Law of the Spirit of Life in Christ Jesus.
This is a New Covenant Law that we are still under. What is this Law?
It is fulfilling the righteousness of the Law (i.e. to love your neighbor - Romans 13:8-10) by walking after the Spirit (See Romans 8:3-4).
Law #2. Sin and Death.
This is in reference to the Old Covenant Law as a whole (i.e. the 613 Old Testament Commands within the Torah). It is called the Law of Sin and Death because you could physically be put to death by not obeying this Law.
What is the relationship of these two laws in Romans 8:2?
Keeping the New Law helps us to be free of the Old Law.
For there is no condemnation to those who are in Christ Jesus who WALK not after the flesh, but after the Spirit. (Romans 8:1).