Verse 21. - And Eleazar the priest said, This is the ordinance of the law (חֻקַּת הַתּורָה, "law-statute, as in Numbers 19:2) which the Lord commanded Moses. There is something peculiar in this expression which points to the probability, either that this paragraph (verses 21-24) was added after the death of Moses, or that "the law was already beginning, even in the lifetime of Moses, to assume the position which it after. wards held - that, viz., of a fixed code to be interpreted and applied by the living authority of the priesthood. This is the earliest instance of the high priest declaring to the people what the law of God as delivered to Moses was, and then applying and enlarging that law to meet the present circumstances. It is no doubt possible that Eleazar referred the matter to Moses, but it would seem on the face of the narrative that he spoke on his own authority as high priest. When we compare the ceremonial of the later Jews, so precisely and minutely ordered for every conceivable contingency, with the Mosaic legislation itself, it is evident that the process of authoritative amplification must have been going on from the first; but it is certainly strange to find that process begun while Moses himself was alive and active.

31:19-24 The Israelites had to purify themselves according to the law, and to abide without the camp seven days, though they had not contracted any moral guilt, the war being just and lawful, and commanded by God. Thus God would preserve in their minds a dread and detestation of shedding blood. The spoil had been used by Midianites, and being now come into the possession of Israelites, it was fit that it should be purified.And Eleazar the priest said unto the men of war, which went to the battle,.... To all the soldiers, officers, and common men:

this is the ordinance of the law, which the Lord commanded Moses; concerning the purification of unclean persons and things, hereby confirming what Moses had said.