What wrong doctrine was being taught? Can you cite the passages where this wrong doctrine is taught? Thank you. Most time lines I’ve seen have Peter baptizing Cornelius around 38 AD well before the Council of Jerusalem. The Navarre commentary says this:
“Up to this point the Gospel has been preached only to Jews. It’s extension to the Samaritans was seen as an announcement of salvation to people who had at one time formed part of the chosen people. By preaching only to Jews, the disciples were having regard to the fact that the people of Israel was the only people chosen by God to be bearers of the divine promises: as such, they had a right to be the first to receive the definitive message of salvation. Our Lord himself acted on this principle, and he told his disciples to preach only you the lost sheep of the house of Israel’(Mt 10:6; cf 15:24).
The Apostles had not yet asked themselves whether this preferential right of the Jewish people to receive the Gospel proclamation implied a certain exclusive right. Now God steps in to make Peter realize that the Good News is meant for all: it is his desire that all be saved and therefore the Christians need to shed the narrow ideas of Judaism as regards the scope of salvation.”