As preparing for teaching the book of Ephesians this fall, one thing stood out to me was that the mystery of Christ, which has now been revealed very clearly, which all Christians should be so thankful...
It seems though that it wasn't so clear to the original readers of this letter that Paul wrote to the church in Ephesus and Asia minor in 1st century.
That was one of reasons why Paul had to write this letter to them at the first place. There was division problem between the Jews and the Gentiles in the church due to their different background. It was hard for the Jews to see that the Gentiles who were so immoral and idolaters came to know Jesus and became believers. Their moral understanding was probably so low compare to the one of the Jews, even if they became Christians because the church was still pretty young when Paul wrote this letter. It was probably no more than 4years old.
So, It is not so hard to imagine that the Jews were saying to the Gentiles, "You can not be sharing same inheritance in the kingdom of God", As matter of fact, Paul himself sounded like confirming what they were thinking of: Eph 5:5 For you may be sure of this, that everyone who is sexually immoral or impure, or who is covetous (that is, an idolater), has no inheritance in the kingdom of Christ and God.
However, if we read the book of Ephesians from 1st chapter to the last carefully, we can recognize that Paul says to the Gentiles again and again that they have exact same inheritance as the Jews have in Christ. How he says this again and again shows that the Gentiles really needed to hear this truth from him. (Read verses below)
Ephesians 3:3-6 how the mystery was made known to me by revelation, as I have written briefly. When you read this, you can perceive my insight into the mystery of Christ, which was not made known to the sons of men in other generations as it has now been revealed to his holy apostles and prophets by the Spirit. This mystery is that the Gentiles are fellow heirs, members of the same body, and partakers of the promise in Christ Jesus through the gospel.
Perhaps, that was why Paul used the word, 'mystery'. He was saying to the them that it was the mystery to the Jews in the Old Testament times before Christ and His Spirit came. Yet, it was made known to the holy apostles (including himself) and prophets by the Spirit and he was saying that sharing the revealed mystery with everyone is his mission. (Eph. 3:7-9) Another reason why he used the word, 'mystery' was possibly to combat against the mystery religions, which people of Ephesus were being so much influenced by. So those who used to be from those religions had thought that only few special ones would have a special knowledge or mystery.
Paul's message here is that the Gentiles are having same promise and inheritance in Christ. And there is no secretive knowledge for only few special ones. The clear revealed truth is that their identity is now the beloved children of God. And he doesn't stop there but goes on further as telling them that then they have to act like one in other chapters of the book. Since they know that they are the beloved children clearly now, so they need to be walking like children of God.
Later on, Paul adds one more point of the mystery of God in 5:32. The mystery is the relationship between Christ and the church, which became one in comparison to the relationship between the husband and wife. Christ is the head and the church is body, which is one body.
So, there is no more mystery of God hidden... He loves to share the truth with everyone, to bring to light for everyone!!! (Eph.3:9)
Once again, this message from Paul encourages me to share this gospel with those who don't know what identity they have in Christ and with those who don't know that the mystery God revealed is to bring to light for everyone...
