Nebuchadnezzar II was Babylon's greatest king. As a conqueror, he was feared by all. A great builder, he had enlarged the city of Babylon to an area of six square miles, beautified it with magnificent buildings, and surrounded it with impenetrable walls. He had hanging gardens around his palace, so spectacular that they were one of the seven wonders of the ancient world.
Nebuchadnezzar had indeed accomplished many things, but he wouldn’t have been able to do any of these things were it not that God had given him his life, his health, his talents, his genetic make-up, his family background, etc. This is true of anybody great or small that accomplishes anything. As Paul notes, What do you have that you did not receive? The answer is nothing.
But full of pride, Nebuchadnezzar bragged, "Is this not great Babylon, that I have built for my royal dwelling by my mighty power and for my majesty?"
God was not pleased with Nebuchadnezzar's overinflated opinion of himself. Listen to what happened next, as found in the book of Daniel: “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 the Most High rules in the kingdom of men, and gives it to whomever He chooses.’”
Then what happened? Daniel continues, “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.”
After seven years he acknowledged God, and his mental health and kingdom were restored. I remember in an “abnormal psychology” class at Tulane, this story was in our textbooks. Of course, as I recall, it discounted the divine element which is critical to the story.
In all the universe, the most devastating example of pride run amok is Lucifer. He was once a highly exalted angelic being. How did Lucifer fall? Through the sin of pride. As C. S. Lewis puts it, “it was through Pride that the devil became the devil.”
To me, the key to overcoming pride is in reversing the phrase “alter ego” (and alter the spelling of alter to altar): We leave our ego on the altar.