So, says the Spirit by Zechariah: “In that day there shall be a fountain (a flowing spring) opened to the house of David and to the inhabitants of Jerusalem, for sin and for _nidda_.”—Zech. xiii, 1. _Nidda_, then, signified a defilement for which that fountain was necessary; and to imagine the ritual uncleanness of _nidda_ to have been healed without ritual water of purifying, would be to suppose the ordinance to contradict the doctrine of the prophets. From these passages it appears: (1.) That the defilement of _nidda_ was a figure representing the sins and apostasies of Israel, viewed as God’s covenant people, his married wife. (2.) That the sprinkling of water is the ordinance divinely chosen to represent the mode of the Spirit’s agency in cleansing from these offenses. (3.) That this defilement and the water of _nidda_ were so intimately associated with each other in the usage of Israel as to serve the prophets for a familiar illustration of the gracious purposes of God, indicated in the texts. If the figure of speech used by the prophet is the proper one for illustrating his doctrine in words, the water of _nidda_ sprinkled on the unclean was the appropriate form by which to express it in ritual action. When, therefore, in the light of these facts, we read the law that the ashes of the heifer “shall be kept for the congregation of the children of Israel for a water of _nidda_,” the conclusion is irresistible, that those defiled with _nidda_ were to be purified with that water. And when to this we add the further declaration concerning “the man that is unclean,” and is not sprinkled with it, and see it illustrated by the case of the Midianite children, the further conclusion is equally evident that, except the peculiar case of the leper, the water of separation was designed for all classes of seven days’ defilement. To all others who were in a state of ritual separation from the communion of Israel, it was essential in order to being restored. SECTION XVII.—_The Baptism of Proselytes._