One of the more peculiar verses in the New Testament is found in Colossians 1:24: “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”
This statement is puzzling to many. Not least, of course, for the reason that it would seem that Paul is in some way denying the sufficiency of the cross. Of course, we know that this could not be possible. There are too many other statements in Paul’s letters where he declares the completeness of Christ’s work (“the is no condemnation for those in Christ!”).
So, what then does Paul mean by saying that in his sufferings, he is “filling what is lacking”?
Before we answer this, we must recognize that suffering is an important aspect of Paul’s theology and practice: For instance, in Romans, Paul makes several statements about suffering: He rejoices in suffering (Romans 5:3), Christians are heirs with Christ only if they suffer with him (8:17-18), Paul wished he could be accursed for his brethren (9:1-5).
Paul says in 2 Corinthians 1:5: “for as we share abundantly in Christ’s suffering, so through Christ we share abundantly in comfort too”. Paul’s theology of suffering becomes the most striking in Philippians 3:9-11:
For his sake I have suffered the loss of all things and count them as rubbish, in order that I may gain Christ and be found in him, not having a righteousness of my own that comes from the law, but that which comes through faith in Christ, the righteousness from God that depends on faith— that I may know him and the power of his resurrection, and may share his sufferings, becoming like him in his death, that by any means possible I may attain the resurrection from the dead.
What are we to make of these strange texts?
It appears that for Paul, to be a Christian means principally to participate in Christ. To participate in his death. To participate in his resurrection. Think now of baptism, which signifies the believer dying and rising with Chris in salvation. The believer is united to Christ by faith, dies to sin and rises to new life.
Salvation for Paul (justification, sanctification, and glorification) is union with Christ, participation in the great theo-drama of the cross. And for Paul, part of this union involved his present sufferings. The persecution. The beatings. The shipwrecks. The hate and mockery of the Jews. Paul was participating in the suffering of Christ through his own suffering. The cross was becoming real within him. He was being more conformed into the image of Christ (2 Cor 3:18).
Many see the cross as an exemption from suffering: Paul saw the cross as something to participate in! And not just the cross. But the resurrection too. This was Paul’s great hope, that all of the suffering he endured would inevitably lead one day to glory!
This gives much deeper meaning to Christ’s call to “pick up your cross”. Discipleship is forming Christ within.
So when Paul says that he “is filling what is lacking”, he means that he is uniting his suffering to Christ’s. He is appropriating Christ’s death within himself personally. That which was accomplished 2,000 years ago was being made real then and there in Paul’s flesh.
And so suffering was, for Paul, an opportunity, not a punishment. It was an opportunity to be conformed more and more to Christ’s death, to the image of Christ. It was a way to make Christ’s death his!