The apostles and elders assembled in Jerusalem to discuss this issue: Did Gentile converts need to be circumcised and submit to the Law of Moses? The doctrine of Christ said: "He who believes and is baptized will be saved" (Mark 16:16). The doctrine of the Pharisees stated: "He who believes, is baptized, is circumcised and obeys the Law of Moses will be saved." That's quite a big difference, don't you think?
If Galatians 2 is indeed parallel to what is recorded here, it appears that some private and public meetings were held on this issue. The private meetings held with James, Peter, and John were very productive, and these men did not doubt the correctness of the position of Paul and Barnabas. James, Peter, and John gave them "the right hand of fellowship" (Gal. 2:9). In other words, they agreed with their teaching and work. Peter publicly affirmed his agreement with Paul's position--the Gentiles did not need to be circumcised or keep the Law of Moses (cf. Acts 15:7ff).
Galatians 2:2 implies that Paul didn't doubt his teaching of the gospel or that his message was lacking since he was not binding circumcision on the Gentile converts. However, others did have doubts and he went to Jerusalem, therefore, as a preventative measure against those who would destroy his work in the Lord. Additionally, that same verse suggests that God commanded him to go, perhaps so this issue could be formally resolved for everyone.
"And when there had been much dispute, Peter rose up and said to them: 'Men and brethren, you know that a good while ago God chose among us, that by my mouth the Gentiles should hear the word of the gospel and believe. So God, who knows the heart, acknowledged them by giving them the Holy Spirit, just as He did to us, and made no distinction between us and them, purifying their hearts by faith. Now therefore, why do you test God by putting a yoke on the neck of the disciples which neither our fathers nor we were able to bear? But we believe that through the grace of the Lord Jesus Christ we shall be saved in the same manner as they'" (Acts 15:7-11).
There was strong disagreement among some regarding this matter, but the leaders seem to be on the same page. Peter reminded everyone that God had clearly authorized the preaching of the gospel to both Jews and Gentiles. Both groups would be saved in the same way--by grace through faith (cf. Eph. 2:8). Both groups had received the Holy Spirit and God was no longer making any distinction between the two, so why should any group of men make a distinction? Those who wanted to bind part or all of the Mosaic law on Gentile Christians were testing God (by arguing against His expressed will). It's as if they believed that God had made a mistake in not requiring Cornelius and his household to be circumcised in conjunction with their baptism into Christ! God had not made a mistake, but some were trying to make laws for God's people which they had no right to create. Besides, Peter argued that the Jews weren't able to bear the Old Law for the centuries they were under it and that it was an unnecessary yoke that would be a hindrance, not a help, to the Gentiles. The law system demanded perfection and no one except Christ was able to live up to the standard. The gospel system or "the faith" was based on God's grace activated by man's obedient faith. That was what both Jews and Gentiles needed!
In conclusion, circumcision might be practiced as a matter of cultural expediency to defuse Jewish bias (e.g., Acts 16:3), but to bind it as a matter of salvation was a perversion of the gospel of Christ (cf. Gal. 1:6,7)! Such could not be tolerated. As a side note, let it be observed that the apostle Paul, by inspiration, labeled those who were requiring circumcision of Gentile Christians as "false brethren" (Gal. 2:4). They came into the church in a deceitful way so that they could behave as spies to undermine the liberty Christians enjoyed and enslave them (cf. Gal. 5:1-4). Some today might wonder why the Pharisees were motivated to behave this way. If they determined that they could not destroy Christianity from the outside, they may have been motivated to join it and corrupt it from the inside to minimize their loss of power and influence among the people. Sadly, it seems impossible to deny the logical conclusion that some Pharisees (i.e., the "false brethren" Paul referred to) obeyed the gospel for the wrong reasons!