Why did judgment fall on Nebuchadnezzar?

When Daniel interpreted the king's second dream he told him that the things his interpreted about the dream would come upon him one year later. Nebuchadnezzar still had time to change his ways and heed Daniel's advice. But he did not. The king did not stop oppressing the poor or repent from his prideful evil ways. In fact the oppression of the people got worse.

At the pinnacle of his prideful arrogance he looked out on the city of Babylon from his lavish palace claiming credit for creating the Babylonian Empire by his own power and might. When the king had the nerve to ask, "Is not this great Babylon, that I have built for a royal dwelling by my mighty power and for the honor of my majesty?" Almighty God responded to this question by teaching Nebuchadnezzar a necessary lesson. He took away his kingdom and made him live like a wild animal eating grass for seven years! He lived like oxen surviving on grass. His hair grew so long it was like the wings of an eagle and feathers and nails grew so long that they looked like the claws of a bird.

Nebuchadnezzar's humiliation in judgment:

"All this came upon King Nebuchadnezzar. At the end of the twelve months he was walking about the royal palace of Babylon. The king spoke, saying, "Is not this great Babylon, that I have built for a royal dwelling by my mighty power and for the honor of my majesty?"

While the word was still in the king's mouth, a voice fell from heaven: "King Nebuchadnezzar, to you it is spoken: the kingdom has departed from you! And they shall drive you from men, and your dwelling shall be with the beasts of the field. They shall make you eat grass like oxen; and seven times shall pass over you, until you know that the Most High rules in the kingdom of men, and gives it to whomever He chooses."

That very hour the word was fulfilled concerning Nebuchadnezzar; he was driven from men and ate grass like oxen; his body was wet with the dew of heaven till his hair had grown like eagles' feathers and his nails like birds' claws."