Albert Barnes Commentary Daniel 5:29

"Then commanded Belshazzar, and they clothed Daniel with purple, and put a chain of gold about his neck, and made proclamation concerning him, that he should be the third ruler in the kingdom." — Daniel 5:29 (ASV)

Then commanded Belshazzar - In compliance with his promise (Daniel 5:16). Though the interpretation had been so fearful in its import, and though Daniel had been so plain and faithful with him, yet he did not hesitate to fulfill his promise. It is a remarkable instance of the result of fidelity, that a proud monarch should have received such a reproof and such a prediction in this manner; and it is an encouragement to us to do our duty, and to state the truth plainly to wicked men. Their own consciences testify to them that it is the truth, and they will see the truth so clearly that they cannot deny it.

And they clothed Daniel with scarlet ... - All this, it would seem, was transacted in a single night, and it has been made an objection, as remarked above, to the authenticity of the book, that such events are said to have occurred in so short a space of time, and that Daniel should have been so soon clothed with the robes of office. On this objection, see Introduction to the chapter, Section I. II. In respect to the latter part of the objection, it may be further remarked here that it was not necessary to fit him with a suit of clothes made expressly for the occasion, for the loose, flowing robes of Eastern people were as well adapted to one person as another, and in the palaces of kings such garments were always on hand. See Harmer’s “Observations on the East,” vol. ii. 392 and following.

Compare Rosenmuller, “Morgenland,” on this passage.

That he should be the third ruler ... - See the notes at Daniel 5:7.