Why were the Gentiles not required to go through the Jewish requirements at the Jerusalem council?
God had already shown, at the house of Cornelius, that He could save Gentiles without requiring them to go through all the Jewish demands. Peter remembered this at the Jerusalem council and used it to defend Paul, enabling Paul to return to Antioch with freedom to preach the Gospel.
Les explains that twelve years had elapsed since the house of Cornelius. Peter and those six Jews had seen what could happen when Gentiles were approached with the Gospel, yet they returned to Jerusalem, where Peter was challenged for going to uncircumcised men. For twelve years there was no further mention of those Gentiles being saved until this Jerusalem council. Les sees the sovereign working of God: God certainly wanted the house of Cornelius saved, but the bigger purpose was to come to Paul's defense at the council. If Peter had not remembered Cornelius, they never would have let Paul go back to Antioch with freedom to preach his Gospel; they would have plagued him. But Peter realized that twelve years earlier God had shown him He could save Gentiles without their going through all that the Jews demanded (Acts 15:7).