In 20 instances, Paul speaks of a mystery or secret (Greek: mystērion) of God in the context of something formerly hidden in meaning but now revealed by God for all to know and understand (Rom 16:25-26; 1 Cor 2:7-10). Often this was in reference to enigmatic Old Testament prophecies of the Messiah. Though the prophesies may not have been understood, Old Testament prophets longed for the Messiah and wondered when and how He would come (1 Pet 1:10-12). It would not be until Jesus taught the apostles the meaning of these mysteries that anyone would fully understand the Old Testament prophecies (Luke 24:44-47). Thus, the apostles became the "stewards of the mysteries of God" (1 Cor 4:1; 2 Pet 3:15-17), and Paul speaks of his privilege of sharing the meaning of these mysteries (Eph 1:8-9; 3:1-5; 5:32).

1. Mystery of the gospel (Eph 6:19; Col 2:2; Col 4:3) and the mystery of the deity of Jesus Christ (1 Tim 3:16). Because of ambiguous prophecies of the Messiah, there were speculations of His arrival and what He would be like (Luke 24:17-21). The Messianic prophecies of Isaiah were made with the Levitical sacrificial laws (Isa 53:1-12) in view: the Servant’s sacrifice was for iniquity (Isa 53:5, 6, 11), transgression (Isa 53:5, 8) and sin (Isa 53:12); it was a guilt offering (Isa 53:10) and as a substitute for human beings (Isa 53:5, 11, 12). Daniel’s vision saw the glorified Son of Man who appears before God in heaven as a human being (Dan 7:13-14). Jesus, while on earth, used the phrase "Son of Man" to identify Himself as God in human form (Matt 9:6; Mark 9:31), and mentioned His return to earth "in clouds" (Mark 13:26; Matt 24:30; 26:64).

To the Jews, Paul explains that the crucifixion of Christ followed the Old Testament sacrificial system where an unblemished animal takes the place of the sinner and its blood makes atonement (2 Cor 5:21). In this process of atonement, Jesus’ sacrifice served as expiation of sin and Jesus Himself served as the High Priest and was symbolically the place of propitiation (Rom 3:25; Heb 9:5)! Jesus was the Servant that Isaiah spoke of.

In contrast to Judaism where God’s people lived under the Law, Paul taught that God’s people lived under the grace of Jesus Christ (2 Cor 3:6-7; Gal 3:19-29). And through Christ, Gentiles have access to the Father (Eph 3:15).

Paul explains this mystery in the form of a hymn or creed: the incarnation of Jesus Christ, His resurrection, exaltation in heaven, gospel call to the Gentiles (nations usually refers to Gentiles), the expression of faith, and His ascension (1 Tim 3:16). And Paul repeatedly mentions Jesus’ resurrection and return to testify to His deity (Rom 14:9; 1 Cor 15:4; 1 Thess 4:14-16).

2. Mystery of His will – the supremacy of Christ (Eph 1:9-10). Other enigmatic Messianic prophecies were the reign of David’s seed (2 Sam 7:12-29), chief cornerstone (Ps 118:22-23), universal reign and repentance of nations (Isa 2:2-4), death swallowed up in victory (Isa 25:6-12), new heavens and new earth (Isa 65:17-25) and an everlasting dominion (Dan 7:13-14).

To the churches around Ephesus, Paul reveals that God’s blessing goes beyond redemption and forgiveness; God provides wisdom and knowledge so that a Believer can discern His will (Eph 1:8-9; Col 1:9). To the Jewish audience, the fulfillment of all messianic hopes is found in Jesus Christ (Eph 1:9-10). God’s plan of salvation is to be carried out in Jesus Christ, and each phase administered at their appointed time.

For those who equated Jesus with unfallen angels ("sons of God" - Job 1:6), Paul wanted to make a distinction. Jesus was more than an angel and more than the Law of Moses (Heb 1:2-3). Jesus was more than the universe; as God’s Firstborn, He created and had dominion over all creation things. The sustenance, unity, meaning and existence of creation were all due to Jesus. All of creation was for Christ, through Christ and universally reconciled by Christ (Col 1:16-17; Rom 8:20-24).

In the end, everything in heaven and earth will be under Christ (1 Cor 15:24-28; Phil 2:9-11). God’s plan of salvation went beyond human beings; the redeeming role of Jesus Christ took cosmic dimensions.

3. Mystery of Gentiles Believers (Rom 11:25; 16:25; Eph 3:3-10; Col 1:25-27). Rooted in the Abrahamic Covenant is the idea that the Messiah would be a blessing to both Jews and Gentile (Gen 12:2-3), and subsequent Old Testament passages refer to the salvation of Gentiles (Isa 11:10; 42:6; 49:6; 60:3; Jer 16:19; Mal 1:11). However the Jews were a people chosen of God (Deut 7:7-8; 14:2), recipients of the covenants (Gen 17:7) and His holy nation (Ex 19:6). The Gentiles were uncircumcised, aliens to Israel, strangers to the covenants and without God or hope (Eph 2:11-22).

In his epistles, Paul writes, on several occasions, about the mystery about Gentile Believers (Eph 3:3-10; Col 1:24-27). Gentile Believers share the same spiritual position and gospel as Jewish Believers (Eph 2:11-22), and together they make up one church body (1 Cor 12:12-27).

In Romans 16:25-26, Paul refers to God’s sovereign election as not limited to those of Jewish ancestry (Rom 9:24-26; 10:18-21).

In Romans 11:25, Paul speaks of the partial hardening of Israel (Isa 6:10; John 12:36-41), and the divine role of Gentile Believers to make the unbelieving Jews jealous so that they will come to faith (Rom 11:11-15). And only after the full number of Gentile Believers have come in will all of Israel will be saved (Rom 11:25).

4. Mystery of the relationship between the church and Christ (Eph 5:31-32) and the mystery of salvation’s plan of a Believer’s glory (1 Cor 15:51). Commonly accepted as a fundamental statement on marriage, Genesis 2:24 is taken literally to mean a male and female is closely joined or united as one. And in the hierarchy of relationships, Paul teaches the Corinthians that God is the head of Christ, Christ is the head of man and man is the head of his wife (1 Cor 11:3).

However, in stating "this great mystery", Paul introduces a profound allegorical interpretation of Genesis 2:24; it is a reference to the relationship between Christ and the church (Eph 5:31-32); it is a marriage relationship.

In the Jewish wedding process, it begins with the arrangement, where the groom’s father pays the bride’s father the "bride price." In an analogous manner, Jesus came and paid the price for His bride the church (Eph 5:25) with His crucifixion. In Paul’s allegorical interpretation, just as a husband ought to love his wife as being one flesh with himself, Christ loves the church not simply, as if it were His body, but because it is His body!

The next step is the period of betrothal. This lasts for at least a year to insure that the bride is pure and a virgin. If children are betrothed to each other, this period can last several years, and during this time, the bride is prepared to be a wife. The apostle Paul makes a reference to the church’s period of betrothal as a period of sanctification and process of purification (2 Cor 11:2; Eph 5:26).

On the wedding day, the groom goes to the bride’s home and fetches her to his home in the bridal procession. In like manner, Jesus will come and fetch His bride in the rapture of the church (1 Cor 15:51-57; 1 Thess 4:13-18).

The wedding ceremony takes place in the home of the groom. For the church, this marriage ceremony takes place in future and, because of His atonement, the church is presented as a pure bride in heaven (Rev 19:6-8).

5. Mystery of Lawlessness (2 Thess 2:7). One of the most enigmatic literary forms in the Bible is Jewish apocalyptic literature. Warning of disaster with a view towards the end times, apocalyptic prophecies usually reflect a hope of the future while the nation of Israel was under the dominion of the Gentile world and pagan cults. The prophet Daniel makes three references to an "abomination that causes desolation" (Dan 9:27; 11:31; 12:11), which Jesus refers to in His prediction of tribulation horrors in His Olivet Discourse (Matt 24:4-28).

Of all the mysteries of God that Paul illuminates, this mystery has scant details and is the most difficult to understand.

Fearful that they may have missed the Day of the Lord, Paul assures the Thessalonians that they did not. Before Jesus returns, there will be a period of apostasy and the man of lawlessness will be revealed (2 Thess 2:3-4). However, the mystery of lawlessness is already at work with false doctrine and deceit, yet the full brunt of evil is restrained by some undefined power (2 Thess 2:6).

While the return of Jesus will be both terrible and glorious, His appearance will destroy the man of lawlessness (2 Thess 2:7-10).

Before the beginning of time, God planned for the crucifixion of His Son to restore His creation and the eventual glorification of His church. It was already prepared in heaven, revealed in Old Testament prophecy and now has taken place in time and history (1 Cor 1:19 quotes Isa 29:14, 1 Cor 2:9 quotes Isa 64:3). Enlightened by the Holy Spirit, Paul is amazed at the magnitude of God’s plan (Rom 11:33; Eph 3:8), and his grasp is sufficient to bind him irresistibly to its service for life and to rule out all boasting of himself (1 Cor 9:15-19).

Paul was an example of a man who did not take for granted the knowledge bestowed upon him.