What does 2 Corinthians 5:18 mean?

Previous verses explained why Paul no longer sees people as he once did. When his understanding of who Christ is changed, his understanding of everyone else did, as well. Once Paul understood that Christ, the Son of God, died to pay for human sin, Paul saw that those who are "in Christ" are entirely new creatures. This happens only when someone comes to Christ through faith and by God's grace (Ephesians 2:8–9). The old, sinful version of those people is over. It's gone. The new has come (2 Corinthians 5:17).

In fact, a new way in which God will reconcile people to Himself has come. Through faith in Christ, any person can be reconciled to God. By using the word reconciled, Paul means our separation from God caused by sin can be removed, once and for all. Forgiven for all their sin, a person can become fully welcomed into a relationship with God.

Paul insists that's exactly what happened to him and his friends. God reconciled them to Himself through faith in Christ. He made them new in Christ. He gave them a permanent and eternal place with Him in His glory through Christ. Once God had done that for them, Paul adds, He immediately gave to them the "ministry of reconciliation." By this, Paul means that God gave them the mission of carrying the gospel, the message of this reconciliation with God, to as many people as possible.