Numbers 19:12

With it] i.e. with the 'water of impurity.'

17-22. The method of purification. The ashes of the heifer are mixed with water from a running stream or spring, and sprinkled upon the unclean person or thing. This is done on the third day after the defilement has been contracted. On the seventh day the unclean person washes his clothes, bathes, and resumes his place in society at even. The penalty of neglect is excommunication. The various parts of the expiatory rite lend themselves easily to symbolical interpretation. The connexion of sin and death, the need of cleansing, and the ever-ready means of purification, are all exemplified. The writer of the Epistle to the Hebrews draws a parallel between the heifer, whose ashes were sanctified to the purifying of the flesh from the defilement arising from contact with dead bodies, and Christ who, also without spot, offered Himself without the camp to God to purge the conscience of believers from dead works, i.e. from works which cause death. See Hebrews 9:13; Hebrews 13:11; Hebrews 13:12.