Paul states here that the call of God is to preach the gospel; but remember what Paul means by “the gospel” viz., the reality of Redemption in our Lord Jesus Christ. We are apt to make sanctification the end-all of our preaching. Paul alludes to personal experience by way of illustration, never as the end of the matter. We are nowhere commissioned to preach salvation or sanctification; we are commissioned to lift up Jesus Christ (John 12:32). It is a travesty to say that Jesus Christ travailed in Redemption to make me a saint. Jesus Christ travailed in Redemption to redeem the whole world, and place it unimpaired and rehabilitated before the throne of God. The fact that Redemption can be experienced by us is an illustration of the power of the reality of Redemption, but that is not the end of Redemption. If God were human, how sick to the heart and weary He would be of the constant requests we make for our salvation, for our sanctification. We tax His energies from morning till night for things for ourselves — something for me to be delivered from! When we touch the bedrock of the reality of the Gospel of God, we shall never bother God any further with little personal plaints.
The one passion of Paul’s life was to proclaim the Gospel of God. He welcomed heart-breaks, disillusionments, tribulation, for one reason only, because these things kept him in unmoved devotion to the Gospel of God.