I'm sorry but you've hit my pet peeve hot button!
I don't think the word authority as we use it today in reference to priesthood is the correct word. Not because it's the wrong word, but because of the hardness of our hearts and attitudes in how we view God and what we think God calls authority.
First off, anybody who thinks in those word terms (having authority from God) is setting themselves up to play God. The idea I now have authority to act in the stead of Jesus Christ is a selfish narcissistic dream. To my thinking it's a lie. The thought should never enter my mind that (I have authority) Here is why.
Yes Jesus did say ( I have chosen you and ordained you), yes Jesus did choose His priesthood. Jesus gave His priesthood spiritual responsibility to look after and tend the sheep... But His Priesthood also have a responsibility, to emulate the same relationship with Jesus/God as Jesus demonstrated between …