The same "law" and works of the law Paul refers to in the book of Galatians is the same "law" he refers to in Romans speaking to the same kind of Jews with the same problem:
In the book of Romans "the Law" refers exclusively to the standard of righteousness that manifests the character of God. - The righteousness of God
1. The law written on conscience manifests this standard - Rom. 2:14-15
Rom. 2:14 For when the Gentiles, which have not the law, do by nature the things contained in the law, these, having not the law, are a law unto themselves:
15 Which shew the work of the law written in their hearts, their conscience also bearing witness, and their thoughts the mean while accusing or else excusing one another
2. This is the character/standard made manifest in the "law and the prophets" a. The Mosaic moral, ceremonial, civil laws
b. The prophets interpretations and applications
c. Romans 3:21
Rom. 3:21 But now the righteousness of God....being witnessed by the law and the prophets;
3. This is the character/standard made manifest in the Person and life of Christ. - Rom. 1:17; 3:21-22; 10:4
Rom. 1:17 For therein is the righteousness of God revealed from faith to faith: as it is written, The just shall live by faith.
Rom. 3:21 But now the righteousness of God without the law is manifested, being witnessed by the law and the prophets;
22 Even the righteousness of God which is by faith of Jesus Christ
Rom. 10:3 For they being ignorant of God’s righteousness, and going about to establish their own righteousness, have not submitted themselves unto the righteousness of God.
4 For Christ is the end of the law for righteousness to every one that believeth.
4. This is the characer/standard that is pursued and obtained ONLY one of two ways: - Rom. 3:27
a. "the law of works" - by personal performance
b. "the law of faith" by substitutionary performance through imputation
Rom. 3:27 Where is boasting then? It is excluded. By what law? of works? Nay: but by the law of faith.
28 Therefore we conclude that a man is justified by faith without the deeds of the law.
5. This is the character/standard that is violated "the law of sin" -Rom. 7:25
Rom. 7;22 For I delight in the law of God after the inward man:....25 I thank God through Jesus Christ our Lord. So then with the mind I myself serve the law of God; but with the flesh the law of sin.
6. This is the character/standard written upon the new heart - Rom. 8:4
Rom. 8:4 That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit.
2 Cor. 3:3 Forasmuch as ye are manifestly declared to be the epistle of Christ ministered by us, written not with ink, but with the Spirit of the living God; not in tables of stone, but in fleshy tables of the heart.
7. This is what the Gentile obtained through faith but what the Jew failed to obtain through works. - Romans 9:30-33
Rom. 9:30 ¶ What shall we say then? That the Gentiles, which followed not after righteousness, have attained to righteousness, even the righteousness which is of faith.31 But Israel, which followed after the law of righteousness, hath not attained to the law of righteousness.
32 Wherefore? Because they sought it not by faith, but as it were by the works of the law. For they stumbled at that stumblingstone;
8. This is the Law that serves as the standard of righteousness in judgement for all who come NOT BY FAITH but by their own works: - Rom. 2:6-10
9. No flesh shall be justified under this law - Rom. 3:20-21.
A. Paul never said anything about the Roman Catholic Church or its dogma or anything relating to them. Paul said specifically in Galatians 2 points are noted from this discourse 1) what "other gospel" were they preaching? Its stated clearly here
Observing the law was the other gospel. That means following Jewish Law as specified in Torah and Talmudic interpretations following a specified haggadah. It means nothing regarding something representing what it symbolizes. 2) what gospel was preached again its listed above Christ against the jewish law. Christ completed the law fulfilled it in his body. Its accomplished. Thus its clearly against law it has nothing to do with baptism.
B)It changed its application between Augustine and Luther very much so. In fact both Calvin and Luther liked Augustine. Which changed the understanding inthe mind of the commoner. Read how things were done during Augustine's time and Luther's time. In fact, Cathedral's, I have been made aware of were common places and the liturgy would be said while people traded their livestock and otherthings during the service. A lot of issues in practice. Sales of indulgences were another change.
C) Its clear by the question you don't know what you are talking about.