How separate were the Israelites supposed to be from the pagan nations around them?

Les explains that the Israelites were God's covenant people, and they were never to intermarry with anybody but those of the nation of Israel. They were to have no real social contact with the pagan people around them. Naturally, they had to do business with them and so forth, but socially they were to remain a separated people. Les also emphasizes that God never instructed the Jew to go out and proselyte the Gentiles or to win the Gentiles even to their religion. God did want those people, but not by virtue of Jewish proselyting or evangelizing, because He was dealing strictly with this covenant nation whom He was going to set aside and make different. This helps explain the New Testament reaction when the apostle Paul began going to the Gentiles; it upset the Jews. For almost two thousand years God had been telling and proving to Israel that they were different, His separated people, and it took them a long time to get that out of their system. That is why Paul and Peter had the confrontation in Galatians chapter 2, because Peter could not get it out of his system that he could sit down and perhaps have a ham sandwich with Gentile believers at Antioch. When his fellow Jews came up from Jerusalem, Paul pointed out that Peter withdrew.