Men in authority over the church?

Book of Mormon
Mosiah 26:8
“Now King Mosiah had given Alma authority over the church.”
Here we enter into strange doctrines not known in the body of Christ, where Christ is the head. Yes in earthly institutions sometimes called church, there is a necessity for someone to have authority. But that the king has the power to grant authority in the church to another man cannot be, for the state has no authority over the church but Christ alone.