A prophet to the nation has several functions. Their main role is to provide guidance to rulers. Prophets will be experts on the law, so they will teach political authorities how to obey it.
When he takes the throne of his kingdom, he is to write for himself on a scroll a copy of this law, taken from that of the priests, who are Levites. It is to be with him, and he is to read it all the days of his life so that he may learn to revere the LORD his God and follow carefully all the words of this law and these decrees (Deut 17:18,19).The prophet to the nation will teach the rulers of the nation how to implement God’s law. As prophets love the law more than others, they will have better understanding of its principles. Their wisdom will assist those who are struggling to interpret the law. Prophets will understand the principles of good government, so they will be able to provide good guidance those in authority.
Ruling a nation can be a frightening task. Many decisions have to be made and most of them are hard, so rulers have always attempted to surround themselves with wise people. The king of Israel knew the benefit of having a prophet close by to help him make decisions.
Now the king of Aram was at war with Israel. After conferring with his officers, he said, "I will set up my camp in such and such a place. The man of God sent word to the king of Israel: "Beware of passing that place, because the Arameans are going down there." So the king of Israel checked on the place indicated by the man of God. Time and again Elisha warned the king, so that he was on his guard in such places. This enraged the king of Aram. He summoned his officers and demanded of them, "Will you not tell me which of us is on the side of the king of Israel?" "None of us, my lord the king," said one of his officers, "but Elisha, the prophet who is in Israel, tells the king of Israel the very words you speak in your bedroom." (2 Kings 6:8-12).Prophets will give supernatural guidance to the political ruler. Because their wisdom is from God, it will be effective.