And by what authority do you feel you can turn someone over to Satan?
1 Corinthians 5:5, 1 Timothy 1:20.
What claim do you have on Paul's authority? He was a called and ordained Apostle of Christ.
The Lord gave Peter and the Twelve power and authority to seal in heaven things that are sealed on earth. But I have never been given this authority merely because Peter was given it. Nor because I've read about it in the scriptures.
Only of the biggest problems the pharisees had is they tried to claim they had authority because they were self proclaimed teachers of the scriptures. And yet when people saw John the Baptist, Christ, or the Twelve they marveled because they taught with authority.
Peter was given the keys to the Kingdom as well. I have never been given those keys. So should I pretend to exercise jurisdiction on those keys, I would be in sin.
Paul was also given authority to cast out Devils. He did this in the Book of Acts. When one who saw Him do this tried to do it, the devil responsed "Jesus I know, Paul I know. But who are you?"
One cannot just assume they have authority from God. A man must be called of God as Aaron was. The scriptures are clear about that. I recommend reading Exodus to see how Aaron was called.