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 Numbers 32:25 )
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.