But what type do you think it is that He commanded Israel to offer a heifer—the men in whom are perfected sins—and to slay and burn it, and then that children should take up the ashes and put them in vessels, and bind the scarlet wool upon wood (behold again the type of the cross and the scarlet wool) and the hyssop, and so the children should sprinkle the people one by one, that they might be cleansed from their sins?
Understand how He speaks to you in simplicity. The calf is Jesus; the men who offer it are the sinners who brought Him to the slaughter. Then they are no longer men, no longer is there the glory of sinners.
The children who sprinkle are those who preached to us the forgiveness of sins and the cleansing of the heart, to whom He gave authority of the gospel to proclaim it—being twelve, for a testimony to the tribes, because there are twelve tribes of Israel.
But why the wool and the hyssop together? Because in His kingdom there shall be evil and foul days, in which we shall be saved; for he who is sick in flesh is healed by the filth of the hyssop.