Matthew Poole and continuators on Numbers 19:9

9 And a man that is clean, shall gather up the ashes of the heifer, and lay them up without the camp in a clean place, and it shall be kept for the congregation of the children of Israel , for a water of separation : it is a purification for sin .

(i. e.) For their use, and therefore in a fit place or places, whence any of them might easily procure it.

Or, To the water, i. e. to be put to the water, or mixed with it.

i. e. Appointed for the cleansing of them that are in a state of separation, who for their uncleanness are separated from the congregation.

Either the Heifer this managed, or the water thus made and sprinkled.

Heb. A sin. i. e. a kind of an offering for sin, or rather a mean for the expiation or cleansing of sin. The name of sin is sometimes given to the punishment of sin, and sometimes to sacrifice or offering for sin.

Marginal references: Heb. 9. 13.