The Bible tells us that the mystery of God is Jesus Christ: “My purpose is that they may be encouraged in heart and united in love, so that they may have the full riches of complete understanding, in order that they may know the mystery of God, namely, Christ, in whom are hidden all the treasures of wisdom and knowledge” (Colossians 2:2–3). A “mystery” in the New Testament is something that had at one time been hidden but is now revealed to God’s people. Jesus spoke of “the mystery of the kingdom of God” (Mark 4:11, NAS) that He was at that point revealing to His disciples. The apostle Paul used the word mystery 21 times in his Epistles. In each case, the “mystery” involved a wonderful declaration of spiritual truth, revealed by God through divine inspiration. A mystery is that “which was not made known to people in other generations as it has now been revealed by the Spirit to God’s holy apostles and prophets” (Ephesians 3:5). The mystery of God’s will is that “which he purposed in Christ, to be put into effect when the times reach their fulfillment—to bring unity to all things in heaven and on earth under Christ” (Ephesians 1:9–10; cf. 1 Corinthians 2:7; Revelation 2:7). The mystery of God is the consummation of God’s plan in bringing His kingdom in Christ to fulfillment. The kingdom had long been prophesied, but the how and the when and the by whom was not clear until the time of Christ. It is in Christ that God has been manifested to all of mankind. As Jesus said, “Anyone who has seen me has seen the Father” (John 14:9). Paul said that he had been commissioned to preach “the word of God in its fullness—the mystery that has been kept hidden for ages and generations, but is now disclosed to the Lord’s people” (Colossians 1:25–26). That is, it is through the apostles that we have been given the capstone of Scripture; their writings, all of which point to Christ—represent the final disclosure of God’s Word to mankind.