Verse 1. - And Moses spake unto the heads of the tribes. The regulations here laid down about vows follow with a certain propriety upon those concerning the ordinary routine of sacrifices (see verse 39 of last chapter), but we cannot conclude with any assurance that they were actually given at this particular period. It would appear upon the lace of it that we have in Leviticus 27, and in this chapter two fragments of Mosaic legislation dealing with the same subject, but, for some reason which it is useless to attempt to discover, widely separated in the inspired record. Nor does there seem to be any valid reason for explaining away the apparently fragmentary and dislocated character of these two sections (see the Introduction). The statement, peculiar to this passage, that these instructions were issued to the "heads of the tribes" itself serves to differentiate it from all the rest of the "statutes" given by Moses, and suggests that this chapter was inserted either by some other hand or from a different source. There is no reason whatever for supposing that the "heads of the tribes" were more interested in these particular regulations than in many others which concerned the social life of the people (such as that treated of in Numbers 5:5-31) which were declared in the ordinary way unto "the children of Israel" at large.

30:1,2 No man can be bound by his own promise to do what he is already, by the Divine precept, forbidden to do. In other matters the command is, that he shall not break his words, through he may change his mind.And Moses spake unto the heads of the tribes,.... Or the princes of them, who could more easily be convened, and who used to meet on certain occasions, and on whom it lay to see various laws put in execution:

concerning the children of Israel; how they ought to conduct and behave in the following case, it being an affair which concerned them all:

saying, this is the thing which the Lord hath commanded; relating to vows. Aben Ezra is of opinion that this was delivered after the battle with Midian, of which there is an account in the following chapter, and is occasioned by what was said, to the tribes of Gad and Reuben, Numbers 32:24.

do that which hath proceeded out of your mouth; to which they replied:

thy servants will do as my lord commandeth; upon which the nature of a vow, and the manner of keeping it, are observed; but the occasion of it rather seems to be what is said towards the close of the foregoing chapter, Numbers 29:39, that the various sacrifices there directed were to be offered in their season, besides the vows and freewill offerings; and when these were ratified and confirmed, and when null and void, and to be fulfilled or neglected, is the principal business of this chapter.