You commented on priests not being able to forgive sins. What about John 20:21-23?
After Jesus' resurrection, he appeared to the apostles.
"Then, the same day at evening, being the first day of the week, when the doors were shut where the disciples were assembled, for fear of the Jews, Jesus came and stood in the midst, and said to them, "Peace be with you." When He had said this, He showed them His hands and His side. Then the disciples were glad when they saw the Lord. So Jesus said to them again, "Peace to you! As the Father has sent Me, I also send you." And when He had said this, He breathed on them, and said to them, "Receive the Holy Spirit. "If you forgive the sins of any, they are forgiven them; if you retain the sins of any, they are retained." Now Thomas, called the Twin, one of the twelve, was not with them when Jesus came" (John 20:19-24).
You must make several leaps to apply this to priests of the Roman Catholic church. First, Jesus was speaking to the apostles, not to priests. Second, Jesus gave the apostles authority to define what is and is not sin. Nothing in this passage states that this is a general authority granted to others beyond the ones to whom it was given. Third, the New Testament does not speak of a priestly class within the church, rather it states that all Christians are priests. "Therefore, to you who believe, He is precious; but to those who are disobedient, "The stone which the builders rejected Has become the chief cornerstone," and "A stone of stumbling And a rock of offense." They stumble, being disobedient to the word, to which they also were appointed. But you are a chosen generation, a royal priesthood, a holy nation, His own special people, that you may proclaim the praises of Him who called you out of darkness into His marvelous light; who once were not a people but are now the people of God, who had not obtained mercy but now have obtained mercy" (I Peter 2:7-10).
What is being stated in John 20:23 is no different from Jesus told the apostles earlier. "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" (Matthew 18:18). The apostles had the authority to tell others what God (heaven) wanted to be bound upon men. It was not an authority to create their own rules, but authority to insist that God's rules would be followed. They were being sent by Christ, just as Christ was sent by God.
Luke also records Christ's commission of the apostles. "Then He said to them, "Thus it is written, and thus it was necessary for the Christ to suffer and to rise from the dead the third day, and that repentance and remission of sins should be preached in His name to all nations, beginning at Jerusalem. And you are witnesses of these things. Behold, I send the Promise of My Father upon you; but tarry in the city of Jerusalem until you are endued with power from on high."" (Luke 24:46-49). Notice that the same elements are mentioned. There is a promise of receiving the Holy Spirit. There is also a commission to preach repentance and remission of sins. But these things were given to the apostles because they were Jesus' witnesses (I John 1:1-4).