Colossians 1:24

Now I rejoice in my sufferings for your sake, and fill up on my part that which is lacking of the afflictions of Christ in my flesh for his body's sake, which is the church.

In this verse Paul, dwelling upon the metaphor of the "body of Christ," thinks of it as being actually Christ, and therefore, like Christ, called to suffer tribulations, hardship and persecutions, thus viewing it as a necessity that just as Christ suffered, so also should Christians (see Romans 8:17; 2 Timothy 2:11,12). Ellis reasoned from this that "Union with Christ involves ipso facto union with Christ's sufferings," but also pointed out that "The sole redemptive sufficiency is in Christ and his atonement."[53] God's imperial "must" is written upon the sufferings of Christians: "Through many tribulations, we must enter into the kingdom of God" (Acts 14:21).