19 that is, that God was in Christ reconciling the world to Himself, not imputing their trespasses to them, and has committed to us the word of reconciliation.
19 that is,
This verse explains the reconciliation of verse 18.
that God was in Christ reconciling the world [mankind] to Himself,
The “world” represents all human beings. This is not universalism, whereby everyone is acceptable in God’s eyes. The idea is that Jesus paid for all sins of all men everywhere (Jn 1:29; 3:16; 4:42; 1 Ti 2:6; He 2:9; 1 Jn 2:2; 4:14). The reason they go to hell is that they reject the One who paid for their sins. The death of Christ has unlimited value for those who believe that He died for them.
“Reconciling the world to Himself” does not mean to convert the lost world to Himself; it is His action of being propitious.
not imputing [counting, accounting] their trespasses [deliberate sins] to them,
The idea here is that God does not charge sins against sinful people to withhold salvation. “Imputing” means that God does not reckon, or account, trespasses against individuals, because Christ fully bore that penalty for them (2 Co 5:21; 1 Pe 2:24; 3:18).
“Trespasses” refers to stepping across a clear, forbidden line. God drew certain lines in the stand to make the crossing of them more egregious. To cross that line is to defy God Himself. To not impute trespasses is to forgive sin (Ro 4:5; Co 2:13).
God is free to reconcile to the person who believes in Christ.
God can turn in friendship to the believer because He reckoned our sins to Christ (imputation) instead of us. God placed our sins on Jesus, who knew no sin. His death replaced our penalty for sinning.
Our message of reconciliation is not penance, doing good, or earning credit with God. The message is simply that Christ’s death reconciled us to God. God will not impute or reckon the penalty of sin to those who believe this. Jesus canceled the record of their transgressions, of which all men are guilty. Further, and additionally, He gives the believer a new record, the record that Christ has before God.