The great privilege of believers is to be Christ’s ambassadors (compare Ephesians 6:20).
as though God were making His appeal through us: Paul does not claim to speak for God. Instead, God speaks through us.
Christ’s redeeming work for sinners allows them to "Be reconciled to God" (see Romans 5:1–11; Ephesians 2:11–22; Colossians 1:15–23). Christian witness centers on this appeal. Paul also urged the rebellious Corinthians to join his side (see 2 Corinthians 6:1).