For this reason I, Paul, a prisoner for Christ Jesus on behalf of you Gentiles—assuming that you have heard of the stewardship of God’s grace that was given to me for you, 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. — Ephesians 3:1-6
Paul speaks here of a mystery, and states clearly what it is: the Gentiles are fellow heirs with the Jews in Jesus. He has been sent to proclaim this good news to the Gentiles.
In the Greek translation of the Old Testament, the Septuagint, the same word for mystery appears in only one place: Daniel 2, 4. Nebuchadnezzar’s dream is spoken of as a mystery. This mystery is revealed to Daniel, and its interpretation is this: including Nebuchadnezzar, four earthly kingdoms would arise in succession. Following these, a stone uncut by hands “became a great mountain and filled the whole earth,” meaning that it would “break in pieces all these kingdoms and bring them to an end, and it shall stand forever.”
God had previously promised a seed to destroy the serpent and undo the curse (Gen. 3). His heel would be bruised, and he would even die and be resurrected, as Abraham expected of Isaac (Gen. 22) and as every offering testified. God had further promised David that this seed would be a son of his, and that his throne would be established forever (2 Sam. 7). The mystery of the old covenant revealed to Nebuchadnezzar and Daniel is that the promised seed would not just be king of Israel, leading the many nations in righteousness, but that he would be emperor of one kingdom that would fill the earth. So we see that in this phase of Israel’s history, even the world emperors became types of the Messiah (Isa. 44-45).
This gives us added insight into Paul’s mystery. Paul further reveals that the Messiah would not establish this world-wide kingdom either by leading Israel in victory over the nations, or by bringing the nations to be incorporated into Israel. Instead, the Messiah establishes a new kingdom that is forged equally out of Israel and the nations. Israel as much as any other nation must submit to this king and kingdom. Thus, Jesus is not only a new Isaac, David, and Cyrus, but he is even pre-Abrahamic: a new Adam, a new Noah, a new Melchizedek. He is the firstborn of an entirely new creation.
This is not entirely unexpected; with each new covenant, Israel had to die to the past and submit themselves to God’s plan for the future. So, for example, when God created a new Israel in David, it took Israel seven and a half years to repudiate Saul and accept David (2 Sam. 2-5). Israel wandered in the wilderness for forty years because of their refusal to repudiate Egypt and Egypt’s gods. This is repeated in the forty years between Jesus’s ascension and the destruction of Jerusalem.
We can also understand Paul’s mystery in terms of Babel (Gen. 11). Jesus will ultimately overcome all of the effects of sin and the curse, so that Babel will progressively be undone. But the way in which this happens is a mystery, a great surprise. The kingdom of Jesus does not return to a single language, either by dominating or destroying all other languages (sorry, Esperanto). Instead, Jesus subverts Babel by welcoming every language into his kingdom, causing every nation and language to confess his lordship. The confusion and cacophony of tongues becomes a harmony and symphony of tongues.
Pentecost, then, is a gospel event, the beginning of the accomplishment of Paul’s mystery, the good news that all nations are brought in to Jesus. We all stand on equal footing before the king of kings.