Why were the twelve apostles sent only to Israel and not to the Gentiles?
The twelve were sent only to Israel because Jesus expressly commanded them to avoid Gentiles and go to the lost sheep of the house of Israel. Their apostolic commission was to Israel, not the Gentiles; the gospel of the uncircumcision was committed to Paul, while Peter received the gospel of the circumcision.
Les teaches that Jesus chose the twelve and commanded them not to go to a Gentile but only to the lost sheep of the house of Israel, so they were apostles of Israel. He stresses that Scripture gives no record of these twelve men ever conducting an actual ministry among Gentiles, though Peter visited Antioch. Their commission was Jewish. Paul then explains that the gospel of the uncircumcision was committed to him by the same God and with the same authority as the gospel of the circumcision committed to Peter, which is the gospel of the Kingdom. Acts 15 is Luke’s account; Galatians is Paul’s first-person account.