What is the meaning of Acts 11:1-3?

1 And the apostles and brethren that were in Judaea heard that the Gentiles had also received the word of God. 2 And when Peter was come up to Jerusalem, they that were of the circumcision contended with him, 3 Saying, Thou wentest in to men uncircumcised, and didst eat with them. (Acts 11:1-3 KJV)

William Burkitt’s Commentary

Observe here, 1. How the Jews, apprehending that Christ and his grace had been only promised and confined to themselves, the call and conversion of the Gentiles became a dreadful stumbling block unto them, even to the believing as well as the unbelieving Jews.

Hereupon observe, 2. How they contended with Peter for eating and conversing with the Gentiles, and especially for admitting them into the gospel-communion without circumcision: Whereas, although God forbad marriages with the Gentiles, he never forbade commerce and conversation with them: No conversation with the Gentiles, in order to the gaining of the Gentiles unto God, was ever forbidden by God; but only such as might withdraw the Jews from God, and corrupt them by idolatry.