If the hearer’s duty in listening to a sermon is to be willing to submit one’s will to God’s will, then one can only do this if the preacher does his duty of demonstrating that what he is saying is God’s will.
When the Westminister Confession refers to the “conscionable hearing” of the Word ,this is what it means– to hear it as an act of conscience, which is bound to obey God. But the conscience is not bound to obey the minister; the minister is only to be obeyed in so far as he demonstrates today hear what God’s will is. Therefore, there is no religious use … in a sermon that merely discloses the minister’s opinion, but does not disclose the opinion of God.
Why Johnny Can’t Preach, 18-19
T. David Gordon