2 Corinthians 5:19
That God was reconciling the world to himself in Christ, not counting men’s sins against them. And he has committed to us the message of reconciliation. (NIV)
1. As this verse is translated in the NIV, it does not have a Trinitarian meaning. Some Trinitarians use the concept from some other translations that “God was in Christ” to prove the Trinity. If the Trinity were true, then God could not be “in” Christ as if Christ were a container. If the Trinity were in fact a true doctrine, then this would be a wonderful place to express it and say, “God was Christ.”
2. The fact that in some versions the verse reads that “God was in Christ” is evidence against the Trinity. If the phrase “God was in Christ” means that Christ is God, then when the Bible says that Christ is “in” Christians (Col. 1:27), it would mean that Christians are Christ. Since we know that Christ being “in” Christians does not make us Christ, then we also know that God being “in” Christ does not make Christ God. The correct understanding of the verse is that God was in Christ in the sense that God placed His spirit in Christ, and Christ is in us in the same way—via the gift of holy spirit.
Snedeker, pp. 442 and 443