Separated to the gospel of God

Romans 1:1
Paul, a bondservant of Jesus Christ, called to be an apostle, separated to the gospel of God

Paul introduces himself before the letter of Romans, calling himself an apostle and more interestingly "separated to the gospel of God". This highlights his whole mission and aim after finding Christ. He has become totally devoted and committed to the gospel to see that it reaches as many people as possible. It is no longer a religious practise or theology for the few who are privileged. Paul has taken on the Great Commission upon himself and was living it out. He would have regarded himself as an instrument to be used by God, hence the passive structure of the sentense describing himself to be separated to the gospel.