When you vow a vow to God, defer not to pay it; for he has no pleasure in fools: pay that which you have vowed.…
The vow is a form of prayer. It is a prayer with an obligation. The worshipper wants something, and, either that he may get it or that he may show his gratitude, he resolves to do a certain thing. In the Old Testament economy the vow was a common form of worship. There was something in it suited to those lower and feebler views of God which obtained in the infancy of the Church. The chief objection to it is, that it lays a man under a bond to do what should always spring from love; that it is likely to be put as a full satisfaction for the religious obligations of the Christian, which yet include the whole life and being; and that there is in it an assumption that, if we do not make the vow, the obligation on our part is not incurred; whereas this is not so, for I may say that whatever is lawful for us to vow is always right for us to do, even if we had not made the vow. Rash. ness and inconsiderateness should not lead us to make any vow, either which we cannot keep, which we will not keep, or which it would be unlawful for us to keep, for such, translated into our language, is no doubt the essential meaning of those words — "Suffer not thy mouth to cause thy flesh to sin; neither say thou before the angel," — that is, the messenger of God, the minister, the priest, who was cognizant of the making of the vow, — "that it was an error: wherefore should God be angry at thy voice, and destroy the work of thy hands?" We are cautioned here not only against rash vows, but against unconsidered and voluminous prayers. Be not rash nor hasty: let thy words be few. Our Saviour cautioned against vain repetitions. Several gross vices in prayer are here indicated. First, voluminous prayer is to be guarded against — the utterance of the same request in many forms, as though God should be affected with the variety and quantity of speech! This, when done as a duty, is an evil; when done for pretence, is a hypocrisy. When we go to God, we should go with some petition which we want granted. We should know what it is; and if we have many petitions, we should have them arranged in proper order, and we should express them simply. There is much prayer without desire; and if God would grant many petitions which are offered up, many a worshipper would be greatly amazed and sadly disappointed. Take for instance our prayers for a new nature, for spiritual-mindedness. Well, we are afraid that there are prayers lying at the back of these petitions giving them the negative. The petitioners do not think there is not a good and a benefit in these things, but they do not want them for themselves, at least not now. A new nature is just what they do not want, but a little more indulgence of the old. They are as full of worldly-mindedness as they can be, and do not wish to have it destroyed. What then? Should we cease to offer up such prayers? No! But what we should do is this: try to get such views of the nature of things sought to be got rid of as shall lead to earnestness in our petitions against them, and to get such views of the blessings prayed for as shall lead us really to desire them. We require to study, that our prayers be of the right kind — that they be not mere verbiage; and, as in going before men for any favour, our words should be few, and well ordered. About the exercise of prayer there are great difficulties, which can only be surmounted by previous study, by constant watchfulness, and by a simple reliance on the Spirit of God, as the source from whom all our inspirations flow.
Parallel VersesKJV: When thou vowest a vow unto God, defer not to pay it; for he hath no pleasure in fools: pay that which thou hast vowed.
WEB: When you vow a vow to God, don't defer to pay it; for he has no pleasure in fools. Pay that which you vow.