PERES, your kingdom is divided and given to the Medes and Persians.”
The word פרס, Pheres, is added, for the word Phersin, meaning his kingdom was divided among the Medes and Persians. I have no doubt that by this word God signified the dispersion of the Monarchy which was at hand. When, therefore, he says Upharsin, and they shall divide, it signifies the instability of the Monarchy, since he wished to destroy or utterly abolish it.
The queen-mother came to his rescue with counsel, for she knew Daniel, a man in whom dwelt the spirit of the holy gods, with light and understanding and wisdom beyond all the other wise men. The king's physicians for melancholy were his own counselors; he needed a physician for his pride, and she knew where to find him.
AI summary
Commenting on Daniel 5:10-29
PERES,.... The singular of "Pharsin", Dan 5:25. The sense of this word is, thy kingdom is divided: which, though it consisted of various provinces, united under Belshazzar, now should be broken and separated from him: and given to the Medes and Persians; to Darius the Mede, and to Cyrus the Persian, who was a partner for a while with his uncle Darius in the government...