continued from yesterday
I wanted to give a possible historical reconstruction of the circumcision controversy in the early church. I'm trying to read between the lines, taking into account the way Acts seems to present things and relying heavily on Paul.
Gentile "God-fearers," men who believed in the God of Israel but did not fully convert, were already a part of the synagogues of the Roman Empire.  It is not clear how many Diaspora Jews were expecting some apocalyptic event to take place in the near future, probably not a lot. Some many have expected God to restore Israel at some point as a nation.
When the message of Christ's second coming and the coming judgment of the world started to spread, it is only natural that such Gentiles would want to be saved from God's wrath. The church at Antioch seems naturally to have started to open the door for this to happen. Why wouldn't they allow a Gentile to be baptized like anyone else? They could be in good standing in the coming kingdom just like they were now, like the "strangers in the land" of old.
And assuming early Christian teaching on the Holy Spirit, what if Gentiles manifested the same signs of having the Spirit as anyone else? This is exactly what the story of Cornelius in Acts 10 indicates. Over the course of Paul's first missionary journey, he finds non-Jews more receptive to his message than Jews. He becomes more and more convinced that this is not only a possibility but in fact his fundamental calling.
But this situation is alarming to conservatives among the early believers. The lines between Jew and Gentile become seriously blurred if the key entry marks are baptism and the Spirit! What about the most important boundary marks of Judaism--circumcision and law-keeping? Jesus himself is remembered as being rather lax when it comes to such issues and we can imagine that Peter and the disciples were not strong on such issues either--many of them were fishermen, after all.
On the other hand, many of their early converts in Jerusalem were surely "apocalyptic conservatives," people like the Essenes who were especially looking for a Messiah to restore Israel and who had a strong sense of angels and demons in spiritual warfare. These are the types that were looking for a purified and restored temple. It creates an inner tension in the earliest Jerusalem community--those who are more in continuity with Jesus' ethic and inclusiveness and those who are attracted to his apocalyptic ideology.
So we see the phenomenon of "Judaizing missionaries." These are individuals who begin to try to pull Christian Jews into line on their law-keeping, especially on purity issues. Eventually they will make their way into Galatia and begin to undermine Paul's teaching there. Their message to Gentile converts was probably something along these lines. "It's nice that you have correctly decided to follow the God of Israel. But you need to go all the way. If you're really serious about following God, you need to become circumcised and fully convert to Judaism, because salvation is of the Jews."
Paul realizes the situation and the Lord tells him that he should go to Jerusalem to secure the support of the Jerusalem leadership. He and Barnabas take uncircumcised Titus as an object lesson. Although James, Peter, and John still think it is optimal for Titus to be circumcised, they do not force him (Gal. 2:3). They adopt a "separate and unequal" policy of sorts. They agree that Titus will not fry on the Day of Judgment, even though he is not circumcised. He is like a stranger in the land of Israel.
The danger of this intermediate position is obvious to James and the Jerusalem church. It may start a slippery slope where Jews start to cut corners on their law-keeping too. Peter visits Antioch to see the church that has sprung up organically. Perhaps Jerusalem is feeling a little out of control. They are the disciples, after all, the ones who actually knew and witnessed Jesus. They are the leaders. What's this megachurch to the north outside of HQ's control?
Peter seems to do just fine. He is fellowshipping with the Gentile converts, eating with them. All is good. Presumably, as a Galilean fisherman, this purity stuff wasn't naturally a big deal to him. But then the messengers come from HQ, from James, Jesus' brother.  "Peter, you are the apostle, the one to whom Jesus first appeared. You have to set the tone. You have to hold the line on purity rules or all the Jewish believers will throw them out the window."
So Peter caves, and Barnabas obediently follows HQ's wishes, whether he agrees with them or not. Jewish believers stop eating with Gentile believers so that they do not become unclean. Perhaps Barnabas is thinking that this is the best compromise for now, that they'll work it out. Two steps forward, one step back, to get ready for the next two steps forward.
Paul completely disagrees. He has kept the Law better than any of these pretenders. He was a Pharisee's Pharisee, after all. It was a joke to see these light weights pretending to be law-observant. "You keep the Law, Peter. I kept the Law. You don't keep the Law."
Paul had previously tried to be in good standing on the basis of law-keeping. He had been perfect at it (Phil. 3:6). It just wasn't what God was looking for. God is justifying, establishing a right relationship with him, through faith, not through these sorts of works of Law. It is the faithful death of Jesus that God counts, appropriated through baptism and the Spirit. The rest is now a distraction, especially for non-Jews.
Eventually, the Jerusalem church would come up with a compromise. If Gentiles will stay away from sexual immorality, if they will not have any blood in the food, if they will not serve meat that has come from a nearby temple or that was strangled so that the blood stayed in it, then Jewish and Gentile believers can eat together.
But Paul was long gone. He completely disagreed because, like Jesus, he believed that clean was a matter of the heart, not a matter of what you eat. When the issue of meat sacrificed to idols comes up at Corinth, he completely ignores the position of the Jerusalem church.
 It is less clear to me by what clear ritual a women might have converted.
 We remember that Jesus' brothers didn't support his ministry when he was on earth. Are we seeing some of the tensions between James and Jesus in the tensions between James and Paul?