"18 “I tell you the truth, whatever you bind on earth will bed bound in heaven, and whatever you loose on earth will be loosed in heaven."
What does that mean?
15 “If your brother or sister sins, go and point out their fault, just between the two of you. If they listen to you, you have won them over. 16 But if they will not listen, take one or two others along, so that ‘every matter may be established by the testimony of two or three witnesses.’ 17 If they still refuse to listen, tell it to the church; and if they refuse to listen even to the church, treat them as you would a pagan or a tax collector.
18 “Truly I tell you, whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven.
In context, this passage is talking about church discipline and forgiveness. Jesus was instructing his first apostles for their teaching, not establishing a general rule for everyone such as priests. If there is a problem with a believer, you should go to them first. (Remember He had just spoke about the false teaching of the rabbis). If the believer refused to listen, you should speak to them with more than one person (believer) about their teachings. This would establish the required witnesses to show that it wasn't just one person "bashing" another unjustly. If, however, the person STILL wouldn't listen, they were to
bring it to the body of believers. If the person insisted on the false teaching, they were to have nothing to do with them. The apostles themselves had been taught by Jesus Himself. If they felt that it was a false teaching that should not be taught, then they had the authority to squelch it. If they considered the error to be of little importance in the end, then they were probably right.