Then prove it from Acts [post-chapter 15] and from the general epistles.
Here’s more.
John wrote to gentiles, “Gaius” in 3 John, and a previous letter was refused by a gentile, “Diotrephes”, along with the people who brought it.
3 John 1:9 (CSB) I wrote something to the church, but Diotrephes, who loves to have first place among them, does not receive our authority.
And more.
Peter was obviously not following the Jewish separation laws that would have had to be a part of the kingdom gospel. Paul called him AND BARNABAS hypocrites for putting on a show of Jewish piety. You’ll have to admit that Barnabas was preaching Paul’s gospel with him, right? And that Peter was “deviating from the truth of the gospel”, right? “Deviating” means he had accepted it, then started to reject it
in hypocrisy.
Galatians 2:12-14 (CSB) 12 For he regularly ate with the Gentiles before certain men came from James. However, when they came, he withdrew and separated himself, because he feared those from the circumcision party. 13 Then the rest of the Jews joined his hypocrisy, so that even Barnabas was led astray by their hypocrisy. 14 But when I saw that they were
deviating from the truth of the gospel, I told Cephas in front of everyone, “If you, who are a Jew, live like a Gentile and not like a Jew, how can you compel Gentiles to live like Jews? ”