‘While the word was in the king's mouth, there fell a voice from heaven, saying, “O king Nebuchadnezzar, to you it is spoken. The kingdom is departed from you. And you will be driven from men, and your dwelling will be with the beasts of the field. You will be made to 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 whoever he will.” '
The voice from heaven warned him of the disturbing result of the illness which would come on him. From it he would learn the lesson that the Most High, and not he, ruled over all things, and that He gave it to whoever He would. In all things God is sovereign, to be revealed by his demoting Nebuchadnezzar, and then by restoring him. Given the situation, the latter was possibly the most remarkable. Even a great king like Nebuchadnezzar was not immune from the chemical activity of the brain, which demonstrated his human weakness.
‘The kingdom is departed from you.' He was about to experience a period when he would no longer rule. Rather he would be like an animal, eating grass, scrabbling in the ground and living as a beast rather than in his present splendid dwelling. The contrast with his previous claim about his dwellingplace was deliberate.
‘Seven times shall pass over you.' This would occur over the divinely appointed period, an extended period of divine judgment. But the very fact that it was so specific also meant that it would have an end.