For if the blood of goats and bulls, and the ashes of an heifer sprinkling those that have been defiled ( κεκοινωμένους, cf. Matthew 15:11, etc; Acts 21:28), sancfifieth to the purifying (literally, unto the purity, καθαρότητα) of the flesh.
In addition to the sin offerings of the Day of Atonement, mention is here made of the red heifer, whose ashes were to be mixed with water for the purification of such as had been ceremonially defiled by contact with dead bodies (for account of which see Numbers 19:1-22).
They are classed together because both were general sin offerings for the whole congregation, representing the idea of continual and unavoidable defilements notwithstanding all the daily sacrifices; the difference between them being that the ashes were reserved for use in known cases of constantly recurring defilement, the sin offerings on the Day of Atonement were for general sin and defilement, known or unknown.
But neither, in themselves, could from their very nature avail for more than outward ceremonial cleansing—" the purity of the flesh." This, however, they did avail for; and, if so, what -must the cleansing power of Christ's offering be?
Its deeper efficacy shall appear from consideration of what it was.