What is the power of truth that Paul says he comes with?

Les explains that Paul is coming with the power of truth, which is the gospel of Christ, and by the power of God. He is also coming in the armor of righteousness on the right hand and on the left. Les notes that Paul often uses contemporary things to make a point, such as the Roman soldier, who carried his weapon in his right hand and his shield in his left. Paul makes the same analogy, but instead of a sword and a shield, both hands hold righteousness. This righteousness is not only for a few believers but for every believer. Les connects this to Romans chapter 3, verse 22, where the righteousness of God is by the faith of Jesus Christ unto all and upon all who believe, with no difference between Jew and Gentile, black and white, rich and poor.