At every stop during his missionary journeys, Paul starts at the synagogue and teaches there until they kick him out. From there, he preaches to the God-fearers. (These are people who believed in one God, had a sense of morality but were not prepared to become Jews). As a result, the membership of those churches he established was made up of both Jews and Gentiles.
This preaching to the Gentiles was not without controversy as Paul and Barnabas were called into Jerusalem to account for themselves as part of the debate about whether the Gentiles would be required to follow the law and be circumcised.
Acts 15:1 Now some men came down from Judea and began to teach the brothers, “Unless you are circumcised according to the custom of Moses, you cannot be saved.” 2 When Paul and Barnabas had a major argument and debate with them, the church appointed Paul and Barnabas and some others from among them to go up to meet with the apostles and elders in Jerusalem about this point of disagreement. …..5 But some from the religious party of the Pharisees who had believed stood up and said, “It is necessary to circumcise the Gentiles and to order them to observe the law of Moses.” 6 Both the apostles and the elders met together to deliberate about this matter. 7 After there had been much debate, Peter stood up and said to them, “Brothers, you know that some time ago God chose me to preach to the Gentiles so they would hear the message of the gospel and believe. 8 And God, who knows the heart, has testified to them by giving them the Holy Spirit just as he did to us, 9 and he made no distinction between them and us, cleansing their hearts by faith. 10 So now why are you putting God to the test by placing on the neck of the disciples a yoke that neither our ancestors nor we have been able to bear? 11 On the contrary, we believe that we are saved through the grace of the Lord Jesus, in the same way as they are.” NET
The council, as you know, decided not to impose circumcision or the law upon the Gentile Christians. Note Peter’s comments on salvation by grace and God not making a distinction between the two groups at the end of the passage.
Ephesians 2:11 Therefore remember that formerly you, the Gentiles in the flesh – who are called “uncircumcision” by the so-called “circumcision” that is performed on the body by human hands – 12 that you were at that time without the Messiah, alienated from the citizenship of Israel and strangers to the covenants of promise, having no hope and without God in the world. NET
This is the starting point for the discussion about what is wrong in the Ephesian church as there is tension between the Jewish Christians and the Gentile Christians. Some Jews saw the Messiah as a spiritual thing, others as political and even some as a mixture of both. Regardless of their individual positions, all Jews expected everything to get better when the Messiah came. Therein lies the problem for those not born Jewish as they are separated from God, the covenants and the Messiah. (When Paul talks circumcision here, he is referring to the covenant rather than the physical act).
The Jewish Christians have a great many advantages through their covenant with God. First is a Messiah who will come and make everything better. Second is citizenship. If you were a Roman citizen, you had certain rights that non-citizens didn’t have. Same thing is true for the circumcised versus the uncircumcised. Third are the covenants of promise that God has made with the Jews which exclude non-Jews. Fourth is hope (and the lack thereof for the Gentiles prior to Christ).
Before moving forward, a distinction needs to be made between the types of hope as there is natural hope and revealed hope. Natural hope is aspirational but it is really nothing more than the crossing your fingers type of hope for something good to happen or that something bad will not happen. The false pagan gods are projections of this aspirational hope.
In contrast, the Jews have a hope that is grounded in God because God has spoken and acted on their behalf. Given this history, it might be a little tough for the Jewish Christians to see these Gentiles in the church and not think about how they are superior. C.S. Lewis talked about how hard it was to recite the creeds in church while looking around the room at the other people who are with him because he is in a room full of people he wouldn’t normally associate with as a man of high intellect and education. This same type of thinking can happen to us today as we look at the world and even at other Christians.
Ephesians 2:13 But now in Christ Jesus you who once were far away have been brought near by the blood of Christ. NHEB
Prior to the Christ event, there was a split with the people of God on one side and the outcasts on the other. All of that has changed as Gentiles now have the same access as Jews. Paul is using language the Jews will understand in explaining that the Gentiles now have the same advantages as the Jews.
The viewpoint of the Jews in Ephesus is that they are far away from the Temple. This same notion of distance holds true in the Temple itself as there were several distinct areas surrounding the Holy of Holies. As a result, some people were further away than others. For example, the outer part was the court of the Gentiles and was open to all although it was fenced to prevent entry into the inner Temple by non-Jews. Next is the outer court (or court of the women) followed by the hall of Israel where the Israelites waited while their sacrifices were being burned. Each area is closer to the Holy of Holies than the previous one. (See: https://www.biblestudy.org/biblepic/interior-diagram-of-temple-in-jerusalem.html for more).
The blood of Christ, although not language often used today, is a shorthand way of talking about God’s work on the cross as it is what happens on the cross that changes everything.
Ephesians 1:7 In Him we have redemption through His blood, the forgiveness of our trespasses, according to the riches of His grace 8 that He lavished on us with all wisdom and understanding. BSB
Colossians 1:19 For God was pleased to have all His fullness dwell in Him, 20and through Him to reconcile to Himself all things, whether things on earth or things in heaven, by making peace through the blood of His cross. BSB
Hebrews 9:11 But now Christ has come as the high priest of the good things to come. He passed through the greater and more perfect tent not made with hands, that is, not of this creation, 12 and he entered once for all into the most holy place not by the blood of goats and calves but by his own blood, and so he himself secured eternal redemption. NET