the mystery that has been kept hidden for ages and generations, but is now disclosed to the Lord’s people. 27 To them God has chosen to make known among the Gentiles the glorious riches of this mystery, which is Christ in you, the hope of glory. (Colossians 1:26-27 NIV).
God has chosen to make the glorious “mystery” of the gospel available to Gentiles, who once were unbelieving pagans. But through the gospel, which most Jews rejected, these unbelieving pagans became believers, and they learned about the “glorious riches” of this previously revealed mystery. These gentiles learned that Christ can dwell in us, which gives us “the hope of glory.” That is sin can be defeated by the power of Christ’s blood, so that we can know that we will go to heaven and be glorified after we die.