Since Gal 3:27-28 say:
“27 For as many of you as were baptized into Christ have put on Christ.
28 There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female; for you are all one in Christ Jesus.”
Is it not therefore sinful for Christians to make distinctions between Jews and Gentiles?
God has given men three comprehensive codes of law to govern their lives. The original one dates from the time of Adam. It is the law by which all men sinned before the Flood and after the Flood up until the time of the giving of the Law to Israel. At the giving of the Law to Israel, there were two laws from God in effect at the same time. There was a new law just for Israel (Dt 4:6-8, 5:3), but it had no effect on the existing law for the Gentiles. The Gentiles continued to be able to sin by violating the original law, just like they had done from the beginning. This situation of parallel laws continued up until Pentecost. On the day of Pentecost in AD 30 men were able for the first time to enter the kingdom of heaven. When they established their citizenship in heaven by B-R-C-B they were delivered from the power of darkness and translated into the kingdom of God’s dear son (Col 1:13). This new kingdom had a new law, the law of Christ. Under this law the citizens of His kingdom may not discriminate against one another by race, condition of earthly servitude, or gender. It had no effect on the other two laws for the people who did not become citizens.
All three laws continue in parallel with each other, but they are in effect for different groups of people. God’s original law for man continues to be in effect for the bulk of humanity. The Law of Moses is in effect for Israel, and the Law of Christ is in effect for the citizens of the Kingdom of Heaven (KOH). For citizens of the KOH (the church) it is unlawful for us to discriminate between Jews and Gentiles, men and women, or slave and free in the kingdom. However, the Law still requires Israelites to maintain separation from unholy people in the world, but for Jew and Gentile brethren in the church, “What God has cleansed, do not call unholy”.
However, Israel was a type of a holy people coming out from among the defiled and keeping themselves pure. They were the type of Christianity. Paul speaks of the Christian’s relationship with worldly people in 2 Cor 6:14-17. In verse 14 Paul says, “Do not be yoked together with unbelievers. For what do righteousness and wickedness have in common? Or what fellowship can light have with darkness?”
Paul goes on to command Christians in verse 17 that they must, “Come out from [the unbelievers] and be separate, says the Lord. Touch no unclean thing, and I will receive you”. From these verses we can see that Paul requires different behavior toward those that are brethren in the kingdom (no discrimination) and those that are in the world (don’t fellowship their unclean behavior). To answer the question, “Isn’t it sinful to discriminate between Jews and Gentiles”, Paul says not only is it not forbidden, it is required.