4. Mose 19:2

Preparation of the Purifying Water. - As water is the ordinary means by which all kinds of uncleanness are removed, it was also to be employed in the removal of the uncleanness of death. But as this uncleanness was the strongest of all religious defilements, fresh water alone was not sufficient to remove it; and consequently a certain kind of sprinkling-water was appointed, which was strengthened by the ashes of a sin-offering, and thus formed into a holy alkali. The main point in the law which follows, therefore, was the preparation of the ashes, and these had to be obtained by the sacrifice of a red heifer. (Note: On this sacrifice, which is so rich in symbolical allusions, but the details of which are so difficult to explain, compare the rabbinical statutes in the talmudical tractate Para (Mishnah, v. Surenh. vi. pp. 269ff.); Maimonides de vacca rufa; and Lundius jd. Heiligth. pp. 680ff. Among modern treatises on this subject, are Bhr's Symbolik, ii. pp. 493ff.; Hengstenberg, Egypt and the Books of Moses, pp. 173ff.; Leyrer in Herzog's Cycl.; Kurtz in the Theol. Studien und Kritiken, 1846, pp. 629ff. (also Sacrificial Worship of the Old Testament, pp. 422ff., Eng. transl., Tr.); and my Archologie, i. p. 58.) Num 19:2 The sons of Israel were to bring to Moses a red heifer, entirely without blemish, and to give it to Eleazar the priest, that he might have it slaughtered in his presence outside the camp. פּרה is not a cow generally, but a young cow, a heifer, הב́לבכיע (lxx), juvenca, between the calf and the full-grown cow. אדמּה, of a red colour, is not to be connected with תמימה in the sense of "quite red," as the Rabbins interpret it; but תמימה, integra, is to be taken by itself, and the words which follow, "wherein is no blemish," to be regarded as defining it still…

This chapter is only concerning the preparing and using of the ashes which were to impregnate the water of purification. The people had complained of the strictness of the law, which forbade their near approach to the tabernacle, Num 17:13. In answer to this complaint, they are here directed to purify themselves, so as that they might come as far as they had occasion without fear. Here is, I. The method of preparing these ashes, by the burning of a red heifer, with a great deal of ceremony (Num 19:1-10). II. The way of using them. 1. They were designed to purify persons from the pollution contracted by a dead body (Num 19:11-16). 2. They were to be put into running water (a small quantity of them), with which the person to be cleansed must be purified (Num 19:17-22). And that this ceremonial purification was a type and figure of the cleansing of the consciences of believers from the pollutions of sin appears by the apostle's discourse, Heb 9:13, Heb 9:14, where he compares the efficacy of the blood of Christ with the sanctifying virtue that was in "the ashes of a heifer sprinkling the unclean."