And the Spirit of the Lord will come upon thee
As a spirit of prophecy, so the Targum; whereby he would be enabled at once to compose psalms and hymns of praise, and sing them in a proper manner, though he had not been trained up in this exercise in the school of the prophets; which made it more wonderful to those that knew him:
and thou shalt prophesy with them:
or "praise" with them, as the same Targum; join with them in singing praises, and perform this service in an orderly manner, as if he had been instructed in it, and used to it:
and shall be turned into another man;
for the Spirit of God would not only operate on him in that way, as to fit him for composing and singing psalms and hymns, but inspire him with wisdom, and prudence, and greatness of mind, and with every qualification necessary for a king; so that he would appear quite another man than he was before, in his outward behaviour, as well as in the endowments of his mind; and from a rustic, an husbandman, a farmer's son, would appear with the air of a prince, and in the majesty of a king; and, as Procopius Gazaeus, have a royal mind or heart given him.