Now I rejoice in my sufferings for you, and I fill up in my flesh what is lacking in regard to Christ’s afflictions for the sake of His body, which is the church.
Now I rejoice in my sufferings for your sake, and in my flesh I am filling up what is lacking in Christ's afflictions for the sake of his body, that is, the church.
It opens the section by naming Paul's sufferings as church-serving.
24Now I rejoice in my sufferings for you, and I fill up in my flesh what is lacking in regard to Christ’s afflictions for the sake of His body, which is the church. 25I became its servant by the commission God gave me to fully proclaim to you the word of God, 26the mystery that was hidden for ages and generations but is now revealed to His saints. 27To them God has chosen to make known among the Gentiles the glorious riches of this mystery, which is Christ in you, the hope of glory. 28We proclaim Him, admonishing and teaching everyone with all wisdom, so that we may present everyone perfect in Christ. 29To this end I also labor, striving with all His energy working powerfully within me.