how could Paul try to “make up what is lacking in afflictions of Christ”?
Two words to remember: consistency and approximate language. Consistency: The only way to misinterpret his words would be to ignore what he said in other places. Almost no one, then or now, could consider that Paul was not trying to take the place of the cross he preached. However, in Colossians 2, some Colossians were trying to make up what they perceived was lacking in Christ by the law, angel worship, and rituals. In Colossians 1, Paul made up what was lacking in their understanding of the sufficiency of Christs afflictions. Paul did this not only by his words in Colossians 1:15-23, but by his life and endurance in suffering, which both validated his words and demonstrated the sufficiency of Jesus. Approximate language: Paul spoke precisely enough for all who wanted to understand him. Paul did not think taking Christs place when he tried to “save some” in 1 Corinthians 9:22, and Paul said Timothy could save his hearers in 1 Timothy 4:16, and James said we could save others in James
