The king's heart is a stream of water in the hand of the Lord;
he turns it wherever he will.
As a farmer irrigates his fields by creating canals to control the direction of the water, so the Lord provides for the fields of the earth by directing the hearts of rulers. Whether these rulers may be righteous or wicked, devout or profane, they nevertheless serve the deeper purposes of God. So it was with Pharaoh, Cyrus, and Artaxerxes. This was the lesson that Nebuchadnezzar learned. However events may appear to be occurring; however mighty the wicked may appear to be and the righteous appear not to be, understand that the very heart of everyone is in the hand of the Lord.
Thus, when you must appear before a "ruler" in your life, pray for God to direct his heart. God is not like us who must hope that by acting one way, he can get a ruler to act as he wants. God controls the very heart. He is not dependent on outside influence. It is amusing to hear a pray-er give God counsel about how to get someone to do his will. Instead of bidding God to do what he deems is necessary, we will advise God as to what events are necessary to take place. We let God know that "the only way to get Bob to change is to..." God merely needs to change the heart, impossible for us but simple for him.
Pray for God to do his will, without giving advice on how to accomplish it. And trust God to do his will. Just as we do not have the wisdom to give God counsel, neither have we the discernment to understand all the ways his will is being carried out. It is not necessary for us to understand all of God's ways. We need merely to be like the child who trusts his father to know what is best and do what is best. We need to know that not only the king's heart is in the hand of the Lord, but that we are held in the palm of his hand.