Colossians 1:24 Updated American Standard Version (UASV)
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, that is, the congregation.
The Bible is quite clear that the corresponding ransom sacrifice of Jesus Christ was one corresponding perfectly to what was lost by Adam. (1 Tim.2:6) It was sufficient to cover over everyone who accepted it and every sin that would result from our human imperfection. (Matt 20:28; John 3:36; Rom 5:9-10; Eph. 1:7, 14; Col. 1:14; 1 Tim 2:5-6; Tit 2:14; Heb. 2:17; 1 Pet. 1:18-19) Thus, the question that begs to be asked, if Christ’s sacrifice was sufficient, why does Paul say that he was “filling up what is lacking in Christ’s afflictions.” Many Scriptures help us to appreciate that suffering is actually a privilege. (Matt. 5:10-12; Jam. 1:12; 5:10-11) Truthfully, it is a gift to suffer in behalf of Christ. This is the point that Paul is making when he says, “I rejoice in my sufferings for your [Christ’s] sake.” All would agree that it is a privilege to have faith in Christ, yet Paul takes this a step further. In this way, giving of ourselves to suffer in behalf of Christ, in his place while he is in heaven, is a gift to Christ. Paul tells us elsewhere, “all who desire to live godly in Christ Jesus will be persecuted.” (2 Tim. 3:12) Let us turn to a modern-day example.
First, let us be honest, no one finds joy or happiness in the fact that someone else is causing him or her hurt. Nor would any sane person find joy in the pain itself. However, suppose that we have a bakery and we service our community with baked goods. In the course of business, we sell baked goods to everyone and anyone, even those who have a lifestyle that we would disagree with, such as drug addicts, alcoholics, gamblers, homosexuals, even unknowingly to those that commit crimes. Then, one day, a lesbian couple comes in the store, we have served them on many occasions but today they have a special request. They ask us to make a wedding cake for their wedding. Now, this would be inappropriate because we are going from providing goods and services to actually playing a part in a homosexual wedding, which is a sin. We beg off and explain why offering to recommend another bakery phone number. The lesbian couple sues our store and worse still the government threatens us with a $150,000.00 fine if we refuse. In the end, we have to close our store and are caught up in a legal battle. We can say without a doubt that we are being persecuted in behalf of Christ. As Paul said, ‘our desire to live godly in Christ Jesus has caused us to be persecuted.” (2 Tim. 3:12) However, as this persecution unfolds, we ‘rejoice in our sufferings for Christ’s sake, we feel grateful for being counted worthy to bear this suffering in his name.
 Gr ekklesia (“assembly;” “congregation, i.e., of Christians”)