NET
24 Now I rejoice in my sufferings for you, and I fill up in my physical body—for the sake of his body, the church—what is lacking in the sufferings of Christ.
Darby
24 Now, I rejoice in sufferings for you, and I fill up that which is behind of the tribulations of Christ in my flesh, for his body, which is the assembly;
KJV
24 Who now rejoice in my sufferings for you, and fill up that which is behind of the afflictions of Christ in my flesh for his body's sake, which is the church: