Then commanded Belshazzar, and they clothed Daniel with scarlet, and put a chain of gold about his neck, and made a proclamation concerning him, that he should be the third ruler in the kingdom.

Jamieson-Fausset-Brown Bible Commentary

29. Belshazzar . clothed Daniel with scarlet-To come from the presence of a prince in a dress presented to the wearer as a distinction is still held a great honor in the East. Daniel was thus restored to a similar rank to what he had held under Nebuchadnezzar (Da 2:48). Godly fidelity which might be expected to bring down vengeance, as in this case, is often rewarded even in this life. The king, having promised, was ashamed before his courtiers to break his word. He perhaps also affected to despise the prophecy of his doom, as an idle threat. As to Daniel's reasons for now accepting what at first he had declined, compare Note, see on [1091]Da 5:17. The insignia of honor would be witnesses for God's glory to the world of his having by God's aid interpreted the mystic characters. The cause of his elevation too would secure the favor of the new dynasty (Da 6:2) for both himself and his captive countrymen. As the capture of the city by Cyrus was not till near daylight, there was no want of time in that eventful night for accomplishing all that is here recorded. The capture of the city so immediately after the prophecy of it (following Belshazzar's sacrilege), marked most emphatically to the whole world the connection between Babylon's sin and its punishment.

Matthew Henry's Concise Commentary

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.