Who sware to Jehovah. One affliction of David is particularly mentioned, That he was filled with perplexity on account of the situation of the Ark. Moses had commanded the people ages before to worship God in the place which he had chosen. (Deuteronomy 12:5.) David knew that the full time had now arrived when the particular place should be made apparent, and yet was in some hesitation -- a state of things which was necessarily attended with much anxiety, especially to one who was so ardently attached to the worship of God, and so vehemently desirous to have the fixed presence of God with the nation, for its defense and government. It is said that he swore to see to the building of the Temple, and to postpone every other consideration to the accomplishment of this object. [1] The objurgation may seem to assume a somewhat too harsh and severe form, when he declares his resolution to refuse sleep, his food, and the common supports of life, until a place should have been set apart for the Temple. To have acted in this way would have been to show an inconsiderate zeal, for it did not become him to prescribe the time to God, nor was it possible for him to endure any number of fasting days or sleepless nights. Then when are we to consider that this vow was taken? I am aware indeed that some Hebrew writers judge it to have been at that period when he fell down trembling at the sight of the angel; but, without denying that the plot of ground was pointed out to him immediately after that circumstance, it is altogether a forced and unsupported conjecture to say, that what had so long been in the thoughts of David was conceived at that exact time. Nor is there anything which should prevent us from supposing that his language is here to be understood as hyperbolical, and that this was not a vow in the strict form of it, but to be understood in a qualified sense that he would never enter his house, nor ascend his couch, without feeling a concern upon this subject. He felt persuaded that the settlement of the sanctuary was intimately connected with the state of the kingdom; and we need not be surprised that so long as he was kept in uncertainty regarding the place of the Temple, he should scarcely have felt assured of his very crown, and have been incapable of sharing the ordinary comforts of life with any satisfaction. Still, where Scripture has been silent we can say nothing certain; and I may throw out these things as what seems to me the most probable interpretation. And I think the sense of the passage may very well bear to be that which I have mentioned, That until informed of the place of the Ark's destined residence, David was full of concern and anxiety, dwelling in his house, or when he lay upon his bed. As to the vow itself, this and other passages afford no ground for supposing, with the Papists, that God approves of whatever vows they may utter, without regard to the nature of them. To vow unto God that which he has himself declared to be agreeable to him, is a commendable practice; but it is too much presumption on our part to say that we will rush upon such vows as suit our carnal inclination. The great thing is that we consider what is agreeable to his will, otherwise we may be found depriving him of that wherein indeed his principal right lies, for with him "to obey is better than sacrifice." (1 Samuel 15:22.)

Footnotes

1 - This oath is not mentioned in any of the historical books of the Old Testament. There is, however, allusion in them to his vow on the subject, although he was forbidden by God to perform it. See 2 Samuel 7:2, 3; and 1 Chronicles 22:7-10.

How he sware unto the Lord - The solemn oath which he took that he would make this the first object; that he would give himself no rest until this was done; that he would sacrifice his personal ease and comfort in order that he might thus honor God. This oath or purpose is not recorded in the history. The fair interpretation of this would be either
(1) that these words properly expressed what was in the mind of David at the time - that is, his acts implied that this purpose was in his heart; or
(2) that this vow was actually made by David, though not elsewhere recorded. Such a vow might have been made, and the remembrance of it kept up by tradition, or it might have been suggested to the author of the psalm by direct inspiration.
And vowed unto the mighty God of Jacob - See Genesis 49:24. The God whom Jacob worshipped, and who had manifested himself so signally to him as a God of might or power.

How he sware unto the Lord - It is only in this place that we are informed of David's vow to the Lord, relative to the building of the temple; but we find he had fully purposed the thing.

How he sware unto the Lord, and vowed unto the mighty God of Jacob. Whom Jacob called so, Genesis 49:24; and to whom he vowed a vow, and is the first we read of that did make one, and it was concerning the house of God, Genesis 28:17; and who had an experience of the might and power of God in protecting and defending him from his brother Esau: of this oath and vow of David no mention is made elsewhere, but no doubt they were made; see Psalm 119:106; of the Messiah's swearing, though upon another account, to whom this may be applied, see Isaiah 45:23.