4. Mose 30:2

Gracious promises are given to the penitent, Deu 30:1-6. The Lord will circumcise their heart, and put all these curses on their enemies, if they hearken to his voice and keep his testimonies, Deu 30:7-10. The word is near to them, and easy to be understood, Deu 30:11-14. Life and death, a blessing and a curse, are set before them; and they are exhorted to love the Lord, obey his voice, and cleave unto him, that they may inherit the land promised to Abraham, Deu 30:15-20.

If a man vow a vow unto the Lord--A mere secret purpose of the mind was not enough to constitute a vow; it had to be actually expressed in words; and though a purely voluntary act, yet when once the vow was made, the performance of it, like that of every other promise, became an indispensable duty--all the more because, referring to a sacred thing, it could not be neglected without the guilt of prevarication and unfaithfulness to God. he shall not break his word--literally, "profane his word"--render it vain and contemptible (Psa 55:20; Psa 89:34). But as it would frequently happen that parties would vow to do things which were neither good in themselves nor in their power to perform, the law ordained that their natural superiors should have the right of judging as to the propriety of those vows, with discretionary power to sanction or interdict their fulfilment. Parents were to determine in the case of their children, and husbands in that of their wives--being, however, allowed only a day for deliberation after the matter became known to them; and their judgment, if unfavorable, released the devotee from all obligation [Num 30:3-8].

If a man vow a vow unto the Lord,.... Which must be in a thing that is lawful to be done, which is not contrary to the revealed will and mind of God, and which may tend to the glory of God, the honour of religion, the service of the sanctuary, the good of a man's self or of his neighbour; or in things purely indifferent, which may, or may not be done, without offence to God or man; as that he will not eat such a thing for such a time, or he will do this or the other thing, as Jarchi observes; who moreover says, that he may forbid himself what is forbidden, and forbid what is free and lawful; but he may not make free or lawful what is forbidden, that is, he may not vow to do a thing which is contrary to the law of God, such a vow will not stand: and he was to be of such an age before he could make a vow that would be valid; according to the Targum of Jonathan, he must be thirteen years of age; it is said in the Misnah (p),"a son of twelve years and one day, his vows are examined; a son of thirteen years and one day, his vows are firm, and they examine the whole thirteenth year before that time; although they say we know to whose name (or on whose account) we vow or consecrate, their vow is no vow, nor their consecration no consecration; but after that time, though they say we know not to whose name (or, on whose account) we vow or consecrate, their vow is a vow, and their consecration a consecration:" or swear an oath to bind his soul with a bond; to his vow adds an oath for the greater confirmation of it, and to lay himself under the greater obligation to perform it: he shall not break his word; or profane it (q) but punctually perform it; men should be careful how they vow, and not rashly do it; but when they have vowed, they ought to perform; see Ecc 5:4, he shall do…

At the head there stands the general rule, "If any one vow a vow to Jehovah, or swear an oath, to bind his soul to abstinence, he shall not break his word; he shall do according to all that has gone out of his mouth:" i.e., he shall keep or fulfil the vow, and the promise of abstinence, in perfect accordance with his word. נדר is a positive vow, or promise to give or sanctify any part of one's property to the Lord. אסּר, from אסר, to bind or fetter, the negative vow, or vow of abstinence. על־נפשׁו אסּר אסר, to take an abstinence upon his soul. In what such abstinence consisted is not explained, because it was well understood from traditional customs; in all probability it consisted chiefly in fasting and other similar abstinence from lawful things. The Nazarite's vow, which is generally reckoned among the vows of abstinence, is called neder in Num 6:2., not issar, because it consisted not merely in abstinence from the fruit of the vine, but also in the positive act of permitting the hair to grow freely in honour of the Lord. The expression "swear an oath" (Num 30:2; cf. Num 30:13) shows that, as a rule, they bound themselves to abstinence by an oath. The inf. constr., השּׁבא, is used here, as in other places, for the inf. abs. (cf. Ges. 131, 4, note 2). יחל, from חלל, for יחל, as in Eze 39:7 (cf. Ges. 67, note 8), to desecrate (his word), i.e., to leave it unfulfilled or break it.

In this chapter we have a law concerning vows, which had been mentioned in the close of the foregoing chapter. I. Here is a general rule laid down that all vows must be carefully performed (Num 30:1, Num 30:2). II. Some particular exceptions to this rule. 1. That the vows of daughters should not be binding unless allowed by the father (Num 30:3-5). Nor, 2. The vows of wives unless allowed by the husband (Num 30:6, etc.).