A Preacher's Charge

Why is it so important that a preacher speak according to the charge of God? Who does a preacher speak on behalf of? What did Paul want Timothy to do with the Word? Why did Paul state the truth simply even those he preached to were superstitious philosophers? Can you separate God and Sovereign? Why did Christ tell Pilate that His kingdom was not of the world? Why did Timothy need reminding that God is Sovereign? Why is Christ THE Faithful Witness? How is God's purpose evident even in the smallest detail of the death of Jesus on the cross? Why did the Christ have to die in order to satisfy God's perfect justice? How does a preacher keep a message without spot and unrebukable?
Is there any king that Christ does not rule over? Why is it by His grace alone and not by a need that the LORD has shared His glory with His chosen creatures in redemption? Why must sinners approach God by the Mediator Jesus the Christ?