Daniel 4:15b & 16

"'Let him be drenched with the dew of heaven, and let him live with the animals among the plants of the earth. Let his mind be changed from that of a man and let him be given the mind of an animal, till seven times pass by him.'" NIV translation

Now, we see that this man will be driven to act like an animal for seven years.

Nebuchadnezzar may have still held out hope that it was speaking of someone else but deep inside he must have been horrified at the thought that it was speaking about him.

Daniel 4:17

"'"The decision is announced by messengers, the holy ones declare the verdict, so that the living may know that the Most High is sovereign over the kingdoms of men and gives them to anyone he wishes and sets over them the lowliest of men."'" NIV translation

God explains the purpose of His actions which is so that men can understand that He is in charge of all creation. Part of that being in charge is the fact that He puts whoever He wants in positions of authority. Usually, these are not the most superior of men but they are there because of the will of God and for His purposes. This is true today as well in that God puts our political leaders in their place to fulfill His purpose and many times they are humbled by the fact that they are being used and cannot do it on their own.