Was it unlawful for a Jew to associate with a Gentile according to Jewish law?
Yes. Scripture records Peter acknowledging that it was unlawful for a Jew to keep company with or come unto one of another nation. Jewish law separated Jews from Gentiles, so entering Cornelius’s house was unlawful. Yet God later showed Peter not to call any man common or unclean.
Les teaches that when Peter spoke to Cornelius and the Roman citizens, he was coming back to the law. Peter acknowledged, “You know that it is an unlawful thing for him that is a Jew to keep company or come unto one of another nation.” These Romans, especially those with duty in Palestine, understood the Jewish community inside out. But Peter added that God had showed him he should not call any man common or unclean. Les explains that God showed him this in the vision of the sheet with clean and unclean animals, and Peter realized it was not just about eating food but about the human race. The gates were now being opened to Gentiles, starting with Cornelius, widening further in chapter 11, and then Paul and Barnabas going out on missionary journeys in chapter 13, mostly to Gentiles.