The Lord hath sworn [in] truth unto David,.... By Nathan the prophet; when he assured him that his house, kingdom, and throne, should be established for ever, 2Sa 7:5; and though there is no mention made of the oath of God, no doubt there was one; or however his word was his oath, as Kimchi observes: besides, the Apostle Peter is express for it that there was one, which was added to his word for the confirmation of it; who is said to swear by himself, because there is no greater; and sometimes by one or other of his perfections, as by his holiness elsewhere; so here in or by his truth, his faithfulness, being the God of truth that cannot lie.
Or it may be rendered, "the Lord hath sworn truth unto David" ; that which is truth: and we may be assured he could not possibly assert or swear anything else; see Ps 89:3;he will not turn from it; change his mind, repent of his oath; make it void, or not fulfil it; for he is unchangeable in his perfections, purposes, and promises; whatever he says and swears to he will certainly perform;of the fruit of thy body will I set upon thy throne; a king upon thy throne, as the Targum: meaning not Solomon; though it is true that the Lord chose him, above all the sons of David, to be his successor in the kingdom, and did place him upon his throne before his death; but a greater than Solomon is here, even the Messiah; as is clear from the testimony of the Apostle Peter, Ac 2:30, by which it appears not only that this promise and oath relate to the Messiah; but that David knew they did, and so understood them; and which have been fulfilled in Jesus of Nazareth: who, as he was notoriously the fruit of David's body according to the flesh, or his human nature; or was of his seed, being born of the Virgin Mary, who lineally descended from him; so he was set upon the throne of David, as it was foretold both by the prophet Isaiah, and by the angel to the virgin, he should, Isa 9:6 Lu 1:32; not in a literal sense; for though he was no doubt right heir to the throne of David so understood, yet his kingdom was not of this world; but he was set as King over God's holy hill of Zion, the church; and reigned over the house of Jacob, the whole Israel of God; the mystical and spiritual Israel, consisting of Jews and Gentiles: his throne, or the seat of his kingdom, is the church; his sceptre the Gospel; his crown the glory true believers in him give him; his laws, by which he rules, are its his word, and written in the hearts of his subjects; and his kingdom shall continue for ever.
tma-ebvn "juravit veritatem", V. L.