Charles Ellicott Commentary 2 Chronicles 29:25

"And he set the Levites in the house of Jehovah with cymbals, with psalteries, and with harps, according to the commandment of David, and of Gad the king`s seer, and Nathan the prophet; for the commandment was of Jehovah by his prophets." — 2 Chronicles 29:25 (ASV)

He set. — Stationed, appointed. Hezekiah restored the ancient choral worship as established by David (1 Chronicles 23:5; 1 Chronicles 23:25).

Psalteries. — Nĕbâlîm, a kind of harp; Greek, νάβλα, νάβλιον.

Harps. — Kinnôrôth. Greek, κινύρα, a sort of lyre, or cittern, or guitar.

Gad ... Nathan. — 1 Chronicles 29:29. This is the only place where the institution of the Levitical minstrelsy is ascribed to the injunctions of prophets; but this is probable in itself, considering that an Israelite king would likely not take any important step, whether in civil or ecclesiastical matters, without consulting the Divine will through the royal prophets. As we know from the cuneiform documents, this was the uniform practice with Assyrian and Babylonian sovereigns. Moreover, prophecy was intimately connected with music (see commentary on 1 Chronicles 25:1).

For so was ... — For by the hand of Jehovah was the commandment; that is, by the hand of his prophets. David’s command was obeyed because it was Divine, having emanated from the prophets who represented Jehovah. (Compare 2 Chronicles 29:15, mentioned above.)