John Gill Bible Commentary

Wherefore my bowels shall sound like a harp for Moab,.... Making a noise as the harp does, and a mournful one as that, when used at funerals; which it makes when it is stricken or played on with the hand, as these were, through the afflictive and punitive hand of God; and which, when stricken, causes a quavering of the strings, to which the inward trembling of the bowels is compared, and is very expressive of the prophet's sympathy, or those he personates; for, when one string of the harp is touched, the rest sound. For these words, as Kimchi says, are spoken in the language of the Moabites; those that survived lamenting the desolate state of their country, which must be very great and affecting; and to show that it was so is the design of the prophet's expressing himself after this manner; for if it was painful to him, it must be much more so to them; so the Targum, "wherefore the bowels of the Moabites shall sound as a harp;'' of the sounding of the bowels, see Isa 63:15, and mine inward parts for Kirharesh: the same with Kirhareseth, Isa 16:7 which being a principal city, the destruction of it was greatly laid to heart. The Targum is, "and their heart shall grieve for the men of the city of their strength;'' it being a strong city, in which they placed their confidence; but being destroyed, and the inhabitants of it, it was very affecting, to which agrees Jer 48:31.