What is the mystery of God?

from the old testament

• The Old Testament focuses on Israel and God’s promises to her. However, there are hints throughout that a hidden mystery will be revealed later. It starts in Genesis 3:15, where God promised a righteous seed to save humanity. That was long before the nation of Israel, indicating that God’s plan of salvation was wider in scope than that one nation.
• Likewise, in Genesis 12:3, there is a hint that through Abraham, “all the families of the earth shall be blessed” (see also Genesis 22:18).
• After Israel was formed and God was preparing to punish her with exile for her sin, God spoke of His servant, who would be Israel’s Savior (e.g., Isaiah 53:5), as also the Savior of the nations. He said, “I am the LORD; I have called you in righteousness; I will take you by the hand and keep you; I will give you as a covenant for the people, a light for the nations, to open the eyes that are blind, to bring out the prisoners from the dungeon, from the prison those who sit in darkness” (Isaiah 42:6–7).
• While the inclusion of the Gentiles and the church remained a mystery, when it is revealed in the New Testament, it does not come out of nowhere but is built upon these and other Old Testament hints.

from the new testament

• Though the Old Testament prophets did not know the extent of the mystery, they had an awareness that something greater was happening. Peter said of them, “Concerning this salvation, the prophets who prophesied about the grace that was to be yours searched and inquired carefully, inquiring what person or time the Spirit of Christ in them was indicating when he predicted the sufferings of Christ and the subsequent glories. It was revealed to them that they were serving not themselves but you, in the things that have now been announced to you through those who preached the good news to you by the Holy Spirit sent from heaven, things into which angels long to look” (1 Peter 1:10–12).
• The “mystery of God” was the revelation of Jesus, the inclusion of the Gentiles, and the creation of the church as the body of Christ (Ephesians 1:22–23) that unified Jews and Gentiles alike (Ephesians 2:14–16).
• Paul explained this mystery, calling it the “mystery of Christ,” saying, “… 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 3:3–6).
• The “mystery of Christ,” also known as the “mystery of God,” is that God’s plan of salvation was always larger than the Jews. Paul said the mystery was revealed through the preaching of Jesus: “Now to him who is able to strengthen you according to my gospel and the preaching of Jesus Christ, according to the revelation of the mystery that was kept secret for long ages but has now been disclosed and through the prophetic writings has been made known to all nations, according to the command of the eternal God, to bring about the obedience of faith” (Romans 16:25–26).
• Colossians 2:2 is one of two passages that specifically use the phrase “mystery of God” (alternatively translated as “God’s mystery”). That passage says that “God’s mystery … is Christ.” The mystery can be summed up as “Christ” because “in whom are hidden all the treasures of wisdom and knowledge” (Colossians 2:3).
• Revelation 10:7, the other passage that uses the “mystery of God” phrase, reads, “in the days of the trumpet call to be sounded by the seventh angel, the mystery of God would be fulfilled, just as he announced to his servants the prophets.” Notice that, as has been said, the mystery is not hidden; it’s already been revealed. At the seventh trumpet, that mystery is to be fulfilled. Note that Christians disagree as to what this trumpet fully signifies, but from the context we learn that at a minimum it will come with the announcement, “The kingdom of the world has become the kingdom of our Lord and of his Christ, and he shall reign forever and ever” (Revelation 11:15). Thus, being a fulfilled mystery means that everything will come to completion or a head at the seventh trumpet. Though the mystery has already been revealed, it is still in the process of reaching its final fulfillment of Christ’s universal reign.

implications for today

Scripture is what is known as progressive revelation. That means that God has slowly revealed Himself and His plans for saving humanity over time (progressively). In that sense, everything was a mystery at one point. However, embedded in that progressive revelation was a mystery hiding in plain sight: God’s plan to save people from every nation, tongue, and tribe (Ephesians 3:4–6). It wasn’t until Jesus came, died, resurrected, and returned to heaven that the pieces came together, revealing that God’s plan was always bigger than the Jewish people. Gentiles and the church were not an afterthought or a “plan B” after the Jews rejected their Messiah. They were always a part of the plan.

Thus, when Scripture talks about “the mystery,” it’s referring to a mystery that has been revealed. Paul marveled at God’s ways of using the Jewish rejection as the means for the world to be saved, while using the Gentile salvation as the means through which the Jews will be saved (Romans 11:11–12, 25–26).

We like to think we “get God,” but the reality is His thoughts are so beyond us that we don’t even know where to start when it comes to thinking like God. Is it possible there are still mysteries to come? Absolutely—in fact, we will discover more about the infinite God for eternity, yet we will never know God entirely.

That said, we already know God truly in Scripture. And after Jesus came, His mystery of salvation was unlocked. How can sinners estranged from God be saved while God remains just and punishes all sin? Through Jesus, who added on a human nature to be like us in every way but without sin (Hebrews 4:15) and then died to save us from our sins. God’s revealed mystery is this: everyone who repents and believes in Jesus will have eternal life.