Near the close of Paul’s letter to the Colossians, he makes a personal plea that his readers will pray for him and Timothy as they continue to preach and teach in various cities: “And pray for us, too, that God may open a door for our message, so that we may proclaim the mystery of Christ, for which I am in chains“ (Colossians 4:3). The term mystery (musterion) typically refers to something not previously revealed.
Earlier in the letter, Paul referred to the Word of God (ton logon tou theou) as the mystery that had been hidden from the ages and generations but has now been revealed (Colossians 1:25–26). Paul adds that the mystery had been revealed not only to the Jews but also to the Gentiles. That mystery, Paul says, is “Christ in you—the hope of glory” (Colossians 1:27). A bit further into the context, Paul refers to God’s mystery as Christ Himself (Colossians 2:2). Throughout his letter to the Colossians, Paul identifies the mystery as Christ and His relationship to believers being revealed in a way not previously communicated. The identity of the Christ had not been revealed in any detail in the Hebrew Scriptures (the Old Testament), though there were, of course, many prophecies anticipating His earthly ministry. From the various theophanies (appearances of God in physical form) in the Hebrew Scriptures, it is evident that the one called Yahweh would later come to earth as a man—Jesus.
Recall Jesus’ claim in John 8:56–58 that He had preceded Abraham. This Yahweh—the preincarnate Christ—had always existed, but at the right time in God’s plan, this Messiah came to earth, born of a virgin. The mystery that is Christ, who had been previously unrevealed, was now clearly manifested in the sight of all. Further, this One not only existed, but He came to earth to express His love by His sacrifice (see John 3:16; Philippians 2:1–11), to have a brotherly kind of relationship (Romans 8:29), and to be intimately known by those who have believed in Him (John 17:3).
As Ephesians is a similar letter written by Paul around the same time, it is helpful to consider Paul’s use of the word mystery in that context as well. He mentions “the mystery“ in Ephesians 1:9, 3:3, and 3:9, but he doesn’t offer any definition in those verses. However, in Ephesians 3:4 Paul refers to the “mystery of Christ,” which he identifies in Ephesians 3:6: “This mystery is that through the gospel the Gentiles are heirs together with Israel, members together of one body, and sharers together in the promise in Christ Jesus.“ In Colossians 4:3 Paul adds that the mystery of Christ was a cause of his own imprisonment (cf. Ephesians 6:19–20).
While Paul uses the term mystery on a number of occasions in his other letters, the reference isn’t always to the mystery of Christ and His relationship with people, as it seems to be in Colossians and Ephesians. Paul recognizes that he is stewarding the mysteries (plural) of God (1 Corinthians 4:1). In Romans 11:25 the mystery is that there would be a partial hardening of Israel. In 1 Corinthians 15:51, the resurrection—and the rapture, more specifically—is referred to as a mystery. There is even a mystery of lawlessness (2 Thessalonians 2:7). While Paul stewards and communicates several of God’s mysteries, he speaks of none in such detail and repetition as he does the mystery of Christ (Colossians 4:3). What a joy to know that Jesus loves us and that His grace toward us was part of God’s plan from the very beginning.