It’s clear in Scriptures that only Jesus Christ can forgive our sins. If so what does John 20:23 mean?
This is a good question. Biblically, only God can forgive sins. Mark 2:1-11 (especially 2:7) makes this clear. Theologically, it only makes sense that God, the one sinned against, can forgive sins committed against God’s law.
With this simple and clear biblical fact, the question of forgiveness is not completely simple. For example, although only God can provide forgiveness of sins against him, it is possible for a human to forgive sins against that person. In fact, Jesus commanded that we forgive those who sin against us. Matthew 18:21-35 is a strong teaching on our need to forgive. One way to put this is that only God can forgive sin, but we can forgive one another. We can forgive the person for what they did, but we cannot forgive them of sins against God.
Having said this, I will have to admit that the interpretation of John 20:23 is not completely obvious. “If you forgive anyone’s sins, they are forgiven. If you refuse to forgive them, then they are unforgiven. At first, this passage seems to contradict what I already said above. It could be (wrongly) interpreted to imply that the apostles could forgive sins against God. However, it does not contradict what was said above. I believe that Jesus is talking about the apostles having authority to publicly forgive sins against the church. If the apostles forgive those who sin against the church, then they should be forgiven by the church. The quote from Jesus may be about “church discipline.” 1 Corinthians chapter five is about sins against the church and the appropraite response to public sins. A person who commits public sins in the church should be “disfellowshipped” by the church. In this sense, the church should not “forgive” the sin against the church until the person who sinned has humbled himself and repented. I believe that Jesus is, essentially, appointing the apostles as leaders of his church. They are to have delegated authority over the church.