Relations between Jews and Gentiles have been problematic for most of the history of the Jewish people. Abraham seems to have been humble about his special relationship with God, and Isaac and Jacob as well. They all seem to have integrated well into the world around them, while staying faithful to YHWH. The Patriarchs, while flawed, knew the Lord, and were honored for it.
Slavery in Egypt was a defining period in the Jewish nation, and they understandably hated the Gentile Egyptians. The Passover highlighted the distinctiveness of the Hebrews as God’s people, and on Mt. Sinai the tribes received the Law which separated them in many ways from those around. Psychologically, such distinctiveness sometimes leads to short term feelings of inferiority and long term feelings of superiority.
Throughout Joshua and the Judges, Israel prevailed over their enemies and gained strength as a nation. God’s order to utterly destroy the Canaanites may have been interpreted by some Jews as proof of the Canaanites/Gentiles unworthiness or inferiority. Though much Israelite suffering was self inflicted, with tribes fighting one another, much of it was oppression at the hands of Gentiles. The years of the kingdom, especially during the height of Hebrew power under David, probably tempted Israel towards great pride in their position under God, even as their conduct before Him deteriorated. At the same time, the prophets continued teaching that God is the God of all nations, including Gentiles, and reminding the Jews that they were chosen not for any superiority in themselves, but rather to be a blessing to the world around (Genesis 12:1-3, Deuteronomy 7:7-9).
The exile was a terrible blow, proving that being “chosen by God” was not enough to secure His temporal blessings. Faith and subsequent obedience were required. The challenge from Hellenism was great. Yet legalism flourished and attitudes hardened towards Gentiles, especially the half Jew and half Gentile Samaritans.
In the first century, Palestinian Jews were generally more negative towards Gentiles, and Diaspora Jews more positive. Pharisees were probably more negative than Sadducees. Nation mattered…many in Israel favored Parthian Gentiles over Roman Gentiles. There were almost as many different Jewish attitudes toward Gentiles as there were Jews.
Some Gentiles completely joined the Jewish religion, forsaking that of their forebears, and were called proselytes. These people often lived in Israel and tried very hard to keep the Law and meet other requirements including allegiance to Israel, following Hebrew personal and social customs, circumcision, prayer, synagogue attendance, and Sabbath observance. They were more accepted by the Jews than others, but not as full members of the Jewish community. Other Gentiles abandoned polytheism and came to Judaism, which is monotheistic. They took on some of the characteristics of Judaism but not all, and were known as God-fearers. These were also more likely to be favorably viewed than Gentiles as a whole.
The most important lesson for Christians is that God chooses His people not because of who we are, but because of who He is. We are sons and daughters of God and brothers and sisters of Christ, and yet we should never take pride in this. Rather we should be thankful that Almighty God chose us, and spread the word as far and fast as possible. He wants to choose every man and woman that He has created, but they must choose Him (John 3:16). Trust, obedience, joy and love are the marks of child of God, not vanity.