None of it. I understand it perfectly because I understand the whole counsel of Scripture and the harmony of Paul and James. SHOW ME YOUR FAITH without your works and I will SHOW YOU my faith By my works. Works is evidence. It is not the cause of salvation. When one claims to have faith but doesn't have works then he is not justified in that claim. When one claims to have faith and shows good works, then he is justified in that claim because true faith is a faith that will work.
Salvation is NOT OF WORKS. But it works. Capisce?
James would not have said "not by faith alone" if he thought one was a consequence of the other. Understand that St. James is not mentioning something on the way to explain something else, like Paul often does in quote you keep repeating. It is his central thought -- unlike your prooftexts.
More tomorrow.
Galatians 2:16 is plainly speaking of the works of the law and not generically of works. We agree: circumcision or other works of obligation, confessional or otherwise are not salvific.
Romans 4:2. Here we have to explain scripture with scripture and look at how St. Paul and St. James describe circumcision of Abraham and the sacrifice of Isaac:
29 Is he the God of the Jews only? Is he not also of the Gentiles? Yes, of the Gentiles also. 30 For it is one God, that justifieth circumcision by faith, and uncircumcision through faith. 31 Do we, then, destroy the law through faith? God forbid: but we establish the law.1 What shall we say then that Abraham hath found, who is our father according to the flesh. 2 For if Abraham were justified by works, he hath whereof to glory, but not before God. 3 For what saith the scripture? Abraham believed God, and it was reputed to him unto justice. 4 Now to him that worketh, the reward is not reckoned according to grace, but according to debt. 5 But to him that worketh not, yet believeth in him that justifieth the ungodly, his faith is reputed to justice, according to the purpose of the grace of God.
(Romans 3, 4)
21 Was not Abraham our father justified by works, offering up Isaac his son upon the altar? 22 Seest thou, that faith did co-operate with his works; and by works faith was made perfect? 23 And the scripture was fulfilled, saying: Abraham believed God, and it was reputed to him to justice, and he was called the friend of God. 24 Do you see that by works a man is justified; and not by faith only?
(James 2)
First note that the context in Romans (and in Galatians) is Christian unity through faith, the unity threatened by circumcision. St. Paul says that Abraham had faith and was circumcised, while a Gentile would have faith but not Jewish law, and that would be reputed to justice. St. James talks of the work of offering up Isaac, and concludes that had his faith been without the cooperation by works, it would not have been perfect faith. So the two apostles do not contradict one another, none of them is teaching salvation by faith alone, and St. James rejects it forcefully.
Romans 3:27 is a marginal reference to "law of works" in relation to boasting. A more to our point statement is in Ephesians 8:8 which you cite next. That clearly speaks to works done for social reward ("boast"). Again, we agree. Whenever works have a temporal reward as motivation, they are not salvific.
2 Timothy 1:9 speaks of divine calling. We agree, God calls whoever He wishes to call. We cannot work up that call. We are discussing the role of works after one has been called to baptism, not before.
2 Timothy 3:16f supports what I say: the Holy Scripture furnishes one to good works. If works were not salvific perhaps "furnished in faith" would have been more apporpriate phrasing, -- but it is not there.
Titus 1:16 simply says that the reprobate, too, are judged by their works.
John 15:16 says that we the chosen ones should bring forth fruit. Indeed fruit is a metaphore for works. It does not say, what you need it to say: it does not say that works is a passive product of faith. Rather, it urges the faithful to do sometihng, just like every other exhortation to good works in the scripture does.
Finally, Matthew 7:14f speaks of fruit, good or evil, coming from trees, also good or evil. This can serve as a prooftext for the predestination of the reprobate, another Calvinist error (it does not prove it because grace tranforms us). It has nothing to do with how our good works relate to faith.
St. Paul, St. James, the Catholic Church, the Orthodox Church, and the faith of our fathers are all in perfect harmony. Works of temporal reward and works of obligation are not salvific. Works cooperating with faith are very much salvific. Nowhere does the scripture say that works are a mere byproduct of faith. This is the matter of plain reading of the scripture, something Protestantism has a big pretense of doing.