The “mystery of God” (Rev. 10:7) is the ironic (foolish, silly, scandalous - 1 Cor. 1:18-31) Gospel of Jesus Christ crucified and risen (the “Lamb who was slain”).  The power of God is mysteriously hidden in the weakness of the suffering and death of God on a Roman cross.  

The mystery of God is that the very precious, powerful and holy Law of God does not make anyone righteous!!!  Righteousness comes through faith in Jesus Christ alone, not through our own efforts. The silly, scandalous, foolish message that the church has been given by God to “witness” about in a hostile world is the mysterious Gospel of unmerited forgiveness and grace that brings about the salvation of the nations. And, as Paul highlights in Philippians 3:10, the church ironically finds its power in sharing in the sufferings of Christ as it witnesses to his ironic, mysterious power in the cross (Romans 1:16-17).