John 20:23 Whose soever sins ye remit, they are remitted unto them; and whose soever sins ye retain, they are retained.
This was spoken to the disciples; there is nothing in this verse that could substantiate applying this to the church, the body of Christ today.
Matthew 16:19 And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven.
The time frame of this is the kingdom of God. The kingdom of God consists of a heavenly and earthly component (1 Chronicles 29:11). The earthly kingdom is in view here based on Matthew 16:19 saying it is on earth. During the earthly kingdom Peter will be given power to remit sins just as the other disciples.
The passage below was written to any man1 John 5:16
If any man see his brother sin a sin which is not unto death, he shall ask, and he shall give him life for them that sin not unto death. There is a sin unto death: I do not say that he shall pray for it.