Chapter 20.

Num. 19
The special nature of all the appointments in this chapter require our separate consideration of it, though the offering is called a sin offering; the words at the close of verse 9, "it is a purification for sin," are literally, "it is a sin offering;" and in verse 17 it should be "take of the ashes of the burning of the sin offering, and running water.”
Also there is strong ground for changing "water of separation," which occurs five times in the chapter, into "water of purification.”
Clearly it is not a sacrifice touching the fundamental relations of the nation to God, for His altar is not referred to, nor does the high priest act; atonement is not said to be made; it is a heifer, not a bullock, and it is killed "without the camp." Their relation to God is at the same time owned by the sprinkling of the blood "towards the tabernacle of the congregation seven times," verse 4.
The term to burn, verse 5, is not that used in connection with the altar, causing sweet savor, but it is one carrying the thought of destroying entirely, consuming. The entire carcass was so burnt; and into the burning, cedar, hyssop and scarlet were to be cast. Cedar, the stately growth in nature, and hyssop, the straggling weed in nature, seem to stand for the highest and lowest inclusively of all that nature furnishes, 1 Kings 4:3333And he spake of trees, from the cedar tree that is in Lebanon even unto the hyssop that springeth out of the wall: he spake also of beasts, and of fowl, and of creeping things, and of fishes. (1 Kings 4:33); while scarlet, the national color, suggests the pride of man, and possibly all that is artificial, for it was a dye obtained by processes.
The true sacrifice is ever the Lord Jesus, here seen bearing the destructive judgment of God; the world crucified to us, and we to it at Calvary. Whether as a source of direct satisfaction or of indirect, "what things were gain to me those I counted loss for Christ, yea doubtless, and I count all things but loss for the excellency of the knowledge of Christ Jesus my Lord," Phil. 3:7, 87But what things were gain to me, those I counted loss for Christ. 8Yea doubtless, and I count all things but loss for the excellency of the knowledge of Christ Jesus my Lord: for whom I have suffered the loss of all things, and do count them but dung, that I may win Christ, (Philippians 3:7‑8). So that Paul could say, "Wherefore henceforth know we no man after the flesh; yea, though we have known Christ after the flesh, yet now henceforth know we Him no more," 2 Cor. 5:1616Wherefore henceforth know we no man after the flesh: yea, though we have known Christ after the flesh, yet now henceforth know we him no more. (2 Corinthians 5:16). Only the new creation in Christ risen could give Paul any satisfaction, the circle of Christ's interests held his heart. All else was to him burned in the cross.
It was the ashes of such a burning that were to be kept laid up, to be used for a water of purification. There is no transgression calling for this sacrifice, the use to which it is put brings no forgiveness; it deals entirely with defilement and cleansing, not with guilt or any failure.
More limited still, the defilement to which it is to be applied is exclusively that which arises from a man's death. "He that toucheth the dead body of any man shall be unclean seven days," verse 11. Then, the tent in which death occurs, then all that come into the tent, and all that is in the tent, all are unclean. Again, he who touches a bone of a man, or a grave, is unclean, and this uncleanness lasts for seven days.
It might be quite right to touch a dead body, or a grave, or a bone; indeed the only record we have of the use of this water in their history, is in Num. 31, where God directs 'Israel to avenge themselves of the Midianites, and the fighting men were kept outside the camp for the cleansing of the water of purification, verses 19-24. Defilement, therefore, may, and must be, clearly defined from guilt. Guilt cannot be rightly contracted, but defilement may.
Still, as it is such, it must be dealt with, and the provision here is the ashes—results of applying fire— of the sacrifice including its blood, and of all natural or worldly things. These applied by means of water, —the written word,—should bring home to our consciences the true value they carry in God's sight,—fit only for judgment,—and our severance from them all in death, by the cross. It is the true and full power of the cross, which we are so apt to neglect, applied to our practice in a scene where the things themselves surround and tempt us continually.
The application of the ashes in water on the third and seventh days, gives a very solemn sense of the importance of the provision, the gravity of defilement, and the serious interference it is with the communion in which we are privileged to live.
So deep and real is this that he who neglected to purify himself was to be cut off from among the congregation, for he defiled the sanctuary of Jehovah.