Albert Barnes Commentary Daniel 4:28

"All this came upon the king Nebuchadnezzar." — Daniel 4:28 (ASV)

All this came upon King Nebuchadnezzar – that is, the threatened judgment came upon him in the form in which it was predicted. He did not repent and reform his life as he was urged to do; and, after God had given him sufficient time to show whether he was inclined to follow Daniel's counsel, God suddenly brought the heavy judgment upon him.

Why he did not follow Daniel's counsel is not stated and cannot be known. It may have been that he was so addicted to a life of wickedness that he would not break off from it, even while admitting he was exposed because of it to such an awful judgment. Many people act similarly, pursuing a course of iniquity even while they admit it will be followed by poverty, disgrace, disease, and death here, and by the wrath of God hereafter. Or, it may be that he did not believe the account Daniel gave and refused to follow his counsel for that reason. Or, it may be that, although he intended to repent, yet, as thousands of others do, he allowed time to pass until God's forbearance was exhausted, and the calamity suddenly came upon him.

It would seem a full year (Daniel 4:29) was given to him to see what the effect of the admonition would be, and then all that had been predicted was fulfilled. His conduct provides a remarkable illustration of the conduct of sinners under threatened wrath: they continue to live in sin when exposed to certain destruction and when warned in the clearest manner of what will come upon them.