May I be willing, Lord, to bear daily my cross for Thee;
Even Thy cup of grief to share—Thou hast born all for me.
(Lead me to Calvary, v4)

Paul makes an interesting comment to the church at Colossi: “Now I rejoice in what I am suffering for you, and I fill up in my flesh what is still lacking in regard to Christ’s afflictions, for the sake of his body, which is the church.” At face value, Paul seems to be saying that Christ’s sufferings were insufficient in some way–but we know from other scripture that this is not the case. Our understanding of this verse is rooted in the understanding of Christian suffering, and of Christ’s suffering.

For clarity’s sake, here’s Matthew Henry’s interpretation:

Both the sufferings of the Head and of the members are called the sufferings of Christ, and make up, as it were, one body of sufferings. But He suffered for the redemption of the church; we suffer on other accounts; for we do but slightly taste that cup of afflictions of which Christ first drank deeply. A Christian may be said to fill up that which remains of the sufferings of Christ, when he takes up his cross, and after the pattern of Christ, bears patiently the afflictions God allots to him.

For the Christian, suffering is an outworking of unity with Christ. Since we are justified before God, our sufferings are no longer a penalty for our own sin and foolishness–Christ paid it all on the Cross, and His suffering was enough. Instead, our sufferings are a bond of fellowship with Jesus, a mark of being His disciple, and a prefix or context for glory.