(22) Though thou knewest.--The whole history of Nebuchadnezzar was known to Belshazzar. He had not, however, learned the moral lesson conveyed by it. He was therefore doubly guilty in the sight of God, because his blasphemy was wilful.

5:18-31 Daniel reads Belshazzar's doom. He had not taken warning by the judgments upon Nebuchadnezzar. And he had insulted God. Sinners are pleased with gods that neither see, nor hear, nor know; but they will be judged by One to whom all things are open. Daniel reads the sentence written on the wall. All this may well be applied to the doom of every sinner. At death, the sinner's days are numbered and finished; after death is the judgment, when he will be weighed in the balance, and found wanting; and after judgment the sinner will be cut asunder, and given as a prey to the devil and his angels. While these things were passing in the palace, it is considered that the army of Cyrus entered the city; and when Belshazzar was slain, a general submission followed. Soon will every impenitent sinner find the writing of God's word brought to pass upon him, whether he is weighed in the balance of the law as a self-righteous Pharisee, or in that of the gospel as a painted hypocrite.And thou his son, O Belshazzar,.... His grandson; See Gill on Daniel 5:1,

hast not humbled thine heart; so as to acknowledge the most high God, and his dependence on him; to own him as his Sovereign, by whom he held his crown and kingdom, and to whom he was accountable; but, on the contrary, lifted up his heart in pride and haughtiness against him:

though thou knewest all this; either by the relation of others, his father and mother, and others; or being an eyewitness of it himself; wherefore his sin was the more aggravated, since he had had an example before him of pride being humbled in a very awful manner, and yet took no warning by it.