A.T. Robertson Commentary 2 Corinthians 5:19

"to wit, that God was in Christ reconciling the world unto himself, not reckoning unto them their trespasses, and having committed unto us the word of reconciliation." — 2 Corinthians 5:19 (ASV)

To wit, that (ως οτ). Latin puts it quoniam quidem. It is an unclassical idiom, but occurs in the papyri and inscriptions (Moulton, Prol., p. 212; Robertson, Grammar, p. 1033). It is in Es 4:14. See also 2 Corinthians 11:21; 2 Thessalonians 2:2. It probably means "how that."

Not reckoning (μη λογιζομενος). What Jesus did (his death for us) stands to our credit (Romans 8:32) if we make our peace with God. This is our task, "the word of reconciliation," that we may receive "the righteousness of God" and be adopted into the family of God.