The question arises from reading Deuteronomy 17 and 1 Samuel 8. In Deuteronomy 17, God assumes that Israel will eventually want a king like the nations around them. He gives instructions for how that king is to live before him and before Israel.
In 1 Samuel 8, when Israel comes to that moment where she does look for a king like the nations around here, Samuel refuses. He sees the folly of Israel’s request. God tells Samuel otherwise but encourages him to warn Israel about the prerogatives of a king.
Samuel presumes that the king will not follow the rules of Deuteronomy 17. Deuteronomy warns against multiplying horses (Deuteronomy 17: 16). The king Samuel speaks of has many horses and his depredations are connected with his stables (1 Samuel 8: 11-12). The king in Deuteronomy does not pile up silver and gold (Deuteronomy 17: 17). Samuel’s king freely taxes the people (1 Samuel 8: 13-17).
The key difference between what happens in Deuteronomy 17 and 1 Samuel 8 is not that Israel wants a king like the nations around them. This is a common comment from the commentators. The fact is both Deuteronomy 17 and 1 Samuel 8 assume that the king is like the nations around Israel.
No, the key difference is that Israel, when she comes before Samuel is rejecting God as king. She is coming with the wrong heart. She is not seeking a king after God’s own heart. If she was she would seek the king of Deuteronomy 17. This is demonstrated in that after Samuel’s warning, Israel gladly accepts the type of king that Samuel describes. If she had been reading Deuteronomy, she would have asked God to apply the warnings of Deuteronomy 17 to the king. Now God does provide a king for Israel and he does warn the king to follow in his ways, but this is out of grace, despite the fact his people rejected him.
Actually, if Israel had been careful to circumscribe their king with the laws that Deuteronomy provides, much of the bad power of the king would have been undermined. The king would have been constrained by the law of God from seeking great riches and honor. God told the king not to collect gold, or horses, or wives. If the kings of Israel had listened, they would not have moved in the direction of tyranny.
But why was it so important to have a king? Did God intend to give Israel a king all along? The king is important because the people of God needed somebody who could give true justice. In the end, judges failed, regular avenues of justice failed, and the people of God needed a person with great wisdom to discern the hardest cases. It is interesting that in Deuteronomy 17 the rules for a king follow the section concerning hard cases. Because of man’s sinful nature, there is no such thing as perfect justice and we crave that justice. The king would fill that role but in order for the king to fulfill that role well he had to be a man after God’s own heart.
In the end the only king that did not fall prey to the temptations mentioned in Deuteronomy 17 was and is the Lord Jesus Christ.
We can conclude that a king is a good thing. The rules of Deuteronomy 17 assume that. 1 Samuel 8 demonstrates that the impatience of the people warped God’s gift of a king to Israel. Israel did not have the patience to put boundaries in place so that the king would not become a tyrant. The role of Jesus Christ assumes that. A king without the boundaries God gave is an evil thing. Israel never asks for the boundaries of Deuteronomy 17 in 1 Samuel 8. Israel rejects the Lord as king because she rejects his teaching for a king.
n.b. I don’t pretend to have the final word on this controverted subject.