Matthew Poole and continuators on Hebrews 9:13

13 For if the blood of bulls and of goats, and the ashes of an heifer sprinkling the unclean, sanctifieth to the purifying of the Flesh:

This Service of Christ in his Sanctuary exceeds the Aaronical, not only for reconciling Souls to God, but purifying of them, as cleared in this and 14 v. The Blood is the same as spoken of v. 12. Bulls here put for Calves, are but to distinguish the Sex; and it is to be noted where our Translators read Oxen, as to Sacrifices in the Old Testament, as particularly, Numb. 7.87. they mean Bulls, for no Oxen were by the Law to be offered to God at all, as Sacrifices, see Levit. 22.17, 18, 19, 21, 22, 23. Because they could not be true Types of the true Sacrifice, which was to perfect them. This Blood was sprinkled on the Mercy-seat and before it, and on the Altar, Levit. 16.14, 19, &c. expiating Sins, and taking away the guilt and legal punishment.

The rite of preparing it, read in Numb. 19.1. to 11. A red Hei[illegible: 1 letter]er was by the People given to the Priest; he was to bring her without the Camp, and order her to be slain, and then take the Blood with his Finger, and sprinkle it towards the Tabernacle seven times; after which she was to be wholly burnt in his sight, with Cedar Wood, Hysop and Scarlet. The Ashes of which were reserved; when they used them they took them in a Vessel, and put running Water to them, and then sprinkled them with a bunch of Hysop on persons legally unclean, v. 18, 19, 20. and so they purified them from that Ceremonial Filth and Pollution; but more of these could purify an unclean Soul, that was left unholy and unclean still.

These sprinklings did sanctify those who were legally unclean, and did procure a legal purity and acceptance of them in the service of the Sanctuary, from which else they were excluded; by this they were lookt on as externally Holy with the Congregation, their Flesh and outward Man being made pure by it for their external Worship.