Only let your conduct be worthy of the gospel of Christ.
Paul never lost his wonder at having been called by God. He understood that the way he lived ought to be worthy of the King who had chosen him. He knew that the mystery of the gospel had been hidden for generations and had only been revealed in his day through the life, death, and resurrection of Jesus Christ (Col. 1:26–27). Paul also understood that until people accept the gospel, they are spiritually dead and therefore without hope (Col. 2:13). As a result of God’s plan of salvation, those who trust in Jesus are not only made alive in Christ but are also adopted as the Father’s children (Rom. 8:16–17). Paul recognized that though the Gospel sounds like foolishness to the world, it is the power of God that brings eternal life to those who accept it.
Because Paul’s life had been radically transformed by the gospel, he was intent on living to honor the gospel that gave him life. It would have been tragic to receive the riches of the gospel and then to live as a spiritual pauper. It would have been disgraceful to be saved from death by the blood of Christ and then show no reverence for that sacrifice. It would have been foolish to accept such love from Christ and then to resent what He asked in return.
The way you live your life ought to be a tribute to the matchless grace that your Lord and Savior, Jesus Christ, has bestowed upon you.