Numbers 19:4 - Joseph Benson’s Commentary on the Old and New Testaments

Sprinkle of her blood directly before the tabernacle This made it in some sort an expiation of sin; for the sprinkling of the blood before the Lord was the chief solemnity in all the sacrifices of atonement: therefore, though this was not done at the altar, yet, being done toward the sanctuary, it was intimated hereby that the virtue and validity of it depended upon the sanctuary, and were derived from it. Thus, in the satisfaction that was made to God by the death of Christ, our great High- Priest, who, by the eternal Spirit, (called, Luke 12:20, the finger of God,) offered himself without spot to God; he did, as it were, sprinkle his own blood directly before the sanctuary, when he said, “Father, into thy hands I commit my spirit.” This also signifies how necessary it was, to the purifying our hearts, that satisfaction should be made to divine justice. This sprinkling of the blood put virtue into the ashes.