A question was posted a decade or so ago on John 20:21-23 and whether or not all men could forgive sins. I couldn’t see that the responder actually addressed what was meant by the Apostles having the authority to forgive sins, except to say that they could bind or loose what they were directed to by the Holy Spirit. The responder went on to say that all men have the right to forgive debts committed against themselves. But Jesus claimed the right to forgive transgressions against deity by his Sonship.
How then could the Apostles have this right, if sins against God is the issue?
Jesus, speaking to the apostles after his resurrection said, "Receive the Holy Spirit. If you forgive the sins of any, their sins have been forgiven them; if you retain the sins of any, they have been retained" (John 20:21-23). The confusion comes because God said, "I, even I, am the LORD, and there is no savior besides Me. ... I, even I, am the one who wipes out your transgressions for My own sake, and I will not remember your sins" (Isaiah 43:11,25). The Jews in Jesus' understood this: "Who can forgive sins but God alone?" (Mark 2:7). Jesus then proved that he had the authority to forgive sins and, thus, was God in the flesh (Mark 2:9-12).
John 20:23 is confusing if you don't pay attention to the tenses. The apostles were told that if they forgive sins, those sins have been forgiven by God. In other words, the apostles were given the right to speak on behalf of God. Their statements are in truth God speaking through them. That is why Jesus started out by saying they were to receive the Holy Spirit (to be inspired by God). Thus, the apostles were not deciding on their own who would be forgiven or not forgiven. They were speaking on behalf of God, with God's authority and power behind them, what God had decided.
This is much like Matthew 18:18 where Jesus said, "Truly I say to you, whatever you bind on earth shall have been bound in heaven; and whatever you loose on earth shall have been loosed in heaven." Jesus was not telling the apostles they could create their own laws. They had the authority to declare and enforce the laws already established in Heaven.
Also, notice that John 20:23 is not speaking necessarily of individuals. Jesus' statement is in the plural. The apostles could, for example, condemn drunkenness in speaking God's law such as in I Corinthians 6:9. Someone might counter, "What right do you have to say I can't get drunk if I want to?" The answer is Jesus gave them the right to pronounce God's judgments on sins and the men who hold on to those sins. They also had the right to declare what God had decided was acceptable to Him.
There were times, however, when the delivery of such judgments was individually done. An example of this is: "For I, on my part, though absent in body but present in spirit, have already judged him who has so committed this, as though I were present. In the name of our Lord Jesus, when you are assembled, and I with you in spirit, with the power of our Lord Jesus, I have decided to deliver such a one to Satan for the destruction of his flesh, so that his spirit may be saved in the day of the Lord Jesus" (I Corinthians 5:3-5). Another is found in Acts 8:20-23.
Thanks for the prompt and detailed response.