God: "I looked for someone to take a stand for me, and stand in the gap" (Ezekiel 22:30)
The authority of the pastor is derived and declarative. In other words, the pastor has authority only insofar as what he is saying is faithful to the Message of the One who has sent him (Mark Dever and Paul Alexander).
It does not seem proper to speak of one attribute of God as being more central and fundamental than another; but if this were permissible, the Scriptural emphasis on the holiness of God would seem to justify its selection.