14 "When you come to the land that the LORD your God is giving you, and you possess it and dwell in it and then say, 'I will set a king over me, like all the nations that are around me,'
15 you may indeed set a king over you whom the LORD your God will choose. One from among your brothers you shall set as king over you. You may not put a foreigner over you, who is not your brother.
God had planned that Israel would have a king over them. The coming Messiah, Jesus, who was still some way off from being born, would eventually be the Eternal King. So it was not a bad thing that Israel might want a king to rule them.
However, there is a specific prediction in the above passage which will come true. This prediction is about the reason why Israel will want a king, and that reasons is not pleasing in the sight of God. Notice that Israel will want a king because all the nations around them have kings. God never wants his people to desire the things of the world so that they can fit in or be like the world. God wants his people to think for themselves about the things that God wants for them.