Music seems to have been a regular accompaniment of prophecy in the "schools of the prophets" (marginal reference), and an occasional accompaniment of it elsewhere Exodus 15:20.

Bring me a minstrel - A person who played on the harp. The rabbins, and many Christians, suppose that Elisha's mind was considerably irritated and grieved by the bad behavior of the young men at Beth-el, and their tragical end, and by the presence of the idolatrous king of Israel; and therefore called for Divine psalmody, that it might calm his spirits, and render him more susceptible of the prophetic influence. To be able to discern the voice of God, and the operation of his hand, it is necessary that the mind be calm, and the passions all in harmony, under the direction of reason; that reason may be under the influence of the Divine Spirit.

The hand of the Lord came upon him - The playing of the harper had the desired effect; his mind was calmed, and the power of God descended upon him. This effect of music was generally acknowledged in every civilized nation. Cicero, in his Tusculan Questions, lib. iv., says, that "the Pythagoreans were accustomed to calm their minds, and soothe their passions, by singing and playing upon the harp." Pythagoraei mentes suas a cogitationum intentione cantu fidibusque ad tranquillitatem traducebant. I have spoken elsewhere of the heathen priests who endeavored to imitate the true prophets, and were as actually filled with the devil as the others were with the true God. The former were thrown into violent agitations and contortions by the influence of the demons which possessed them, while the latter were in a state of the utmost serenity and composure.

But now bring me a minstrel,.... A piper, a man that knows how to play upon the harp, as the Targum; according to Procopius Gazaeus, this was one of the Levites he ordered to be fetched, who was used to the spiritual melody of David, and could play on musical instruments as he directed. This he did to allay his passion, and compose his spirits, ruffled at the sight of Jehoram, and to fit him to receive prophetic inspiration, which sometimes came upon the Lord's prophets when thus employed, see 1 Samuel 10:5. Some think (h) the music the prophet called for is that sort the Greeks call "harmony", which is the gravest and saddest, and settles the affections:

and it came to pass, when the minstrel played, that the hand of the Lord came upon him; the spirit of prophecy, as the Targum, which came by the power of God, and as a gift from his hand.

(h) Weemse's Christ. Synagog. l. 1. c. 6. sect. 4. p. 143.

He then sent for a minstrel, to collect his mind from the impressions of the outer world by the soft tones of the instrument, and by subduing the self-life and life in the external world to become absorbed in the intuition of divine things. On this influence of music upon the state of the mind, see the remark on 1 Samuel 16:16, and Passavant's Untersuchungen ber den Lebens-magnetismus, p. 207 (ed. 2). - As the minstrel was playing, the hand of the Lord came upon him (והיה according to the later usage for ויהי, as in 1 Samuel 17:48, etc.; compare Ewald, 345, b., and יהוה יד as in 1 Kings 18:46), so that he said in the name of the Lord: "Make this valley full of trenches (עשׂה, inf. abs. for the imperative; for גּבים גּבים see Ges. 108, 4); for thus saith the Lord, ye will see neither wind nor rain, and this valley will be filled with water, that ye may be able to drink, and your flocks and your cattle." גּבים are trenches for collecting water (vid., Jeremiah 14:3), which would suddenly flow down through the brook-valley. This large quantity of water came on the (following) morning "by the way of Edom" (2 Kings 3:20), a heavy fall of rain or violent storm having taken place, as is evident from the context, in the eastern mountains of Edom, at a great distance from the Israelitish camp, the water of which filled the brook-valley, i.e., the Wady el Kurahy and el Ahsy (see at 2 Kings 3:9) at once, without the Israelites observing anything either of the wind, which always precedes rain in the East (Harmar, Beobb. i. pp. 51, 52), or of the rain itself. מקניכם are the flocks intended for slaughtering, בּהמתּכם the beasts of burden.

But now bring me a minstrel. And it came to pass, when the minstrel {l} played, that the hand of the LORD came upon him.

(l) He sang songs to God's glory, and so stirred up the prophets heart to prophecy.

3:15 Minstrel - One that can sing and play upon a musical instrument. This he requires, that his mind which had been disturbed at the sight of wicked Jehoram, might be composed, and that he might be excited to more fervent prayer whereby he was prepared to receive the prophetic inspiration. Those that desire communion with God must keep their spirits quiet and serene. All hurry of spirit, and all turbulent passions, make us unfit for divine visitations. The hand, and c. - The spirit of prophecy, so called, to note that it was no natural nor acquired virtue inherent in him; but a singular gift of God, given to whom and when he pleased.

15. bring me a minstrel-The effect of music in soothing the mind is much regarded in the East; and it appears that the ancient prophets, before entering their work, commonly resorted to it, as a preparative, by praise and prayer, to their receiving the prophetic afflatus.

the hand of the Lord-a phrase significantly implying that the gift of prophecy was not a natural or inherent gift, but conferred by the power and grace of God.

3:6-19 The king of Israel laments their distress, and the danger they were in. He called these kings together, yet he charges it upon Providence. Thus the foolishness of man perverteth his way, and then his heart fretteth against the Lord, Pr 19:3. It was well that Jehoshaphat inquired of the Lord now, but it had been much better if he had done it before he engaged in this war. Good men sometimes neglect their duty, till necessity and affliction drive them to it. Wicked people often fare the better for the friendship and society of the godly. To try their faith and obedience, Elisha bids them make the valley full of pits to receive water. Those who expect God's blessings, must dig pools for the rain to fill, as in the valley of Baca, and thus make even that a well, Ps 84:6. We need not inquire whence the water came. God is not tied to second causes. They that sincerely seek for the dew of God's grace, shall have it, and by it be made more than conquerors.