The fifteenth chapter of Acts, which is often headlined as “The Jerusalem Council,” is predicated on the Gentile question. The chapter opens with “Now some men came down from Judea and began to teach the brothers, ‘Unless you are circumcised according to the custom of Moses, you cannot be saved.’” (Acts 15:1) This took place in Antioch, which was a major center of the church. “When Paul and Barnabas had a major argument and debate with them, the church appointed Paul and Barnabas and some others from among them to go up to meet with the apostles and elders in Jerusalem about this point of disagreement” (15:2).
Luke goes on to report that “When they arrived in Jerusalem, they were received by the elders, and they reported all the things God had done with them. But some from the religious party of the Pharisees who had believed,” in Jesus, and therefore were part of the church, “stood up and said, ‘It is necessary to circumcise the Gentiles and to order them to observe the law of Moses.’” (15:4-5) Effectively, this circumcision and observance of the law of Moses, which would be an adherence to the marks of the covenant as evidence of inclusion in the people of the Creator God, would make these Gentiles into Jews.
Peter would stand and declare that “some time ago God chose me to preach to the Gentiles so they would hear the message of the Gospel and believe” (15:7b). It is here worth remembering that the use of “gospel” was not to be disconnected from its use by Rome and by Caesar, as announcements about Caesar (particularly in connection with his cult and his worship) were said to be “gospel.” It was a term with which all the people of the empire would have been familiar, so the announcement of a “gospel” was not a novelty in the least. The novelty was that it was being used in reference to Jesus and His kingdom---the new, true King of a new, true kingdom.
With that in mind then, as it would have been in the minds of his hearers and in the minds of those that would later hear Luke’s account of the church (Acts), Peter continues, saying “God, who knows the heart, has testified to them by giving them the Holy Spirit just as He did to us, and He made no distinction between them and us, cleansing their hearts by faith” (15:8). This “faith” was the confession of Jesus’ lordship, as demonstrated by the close of his statement, which was “we believe that we are saved through the grace of the Lord Jesus, in the same way we are” (15:11).
This was remarkable, in that Peter, as a Jew, was devaluing the marks of the covenant, elevating faith in Jesus, which could only come about by what was considered to be the gracious act of the Creator God via His Spirit (who would believe that a man that was crucified by the Romans was the resurrected Messiah and Lord of all?), as the means by which a person, be it Jew or Gentile, enters in upon the covenant that this God first made with Abraham.
The point being made, and it is the point upon which Paul would seize with great tenacity, was that Gentiles were to be accepted into the covenant as Gentiles, and that the covenant was being extended to Gentiles, rather than still being limited to those who were Jews by birth or who had become Jews via Judaizing (by circumcision and adoption of the covenant markers).