When the Israelites had entered the wilderness and had come to Mount Sinai, where God intended to give them His covenant, He “said unto Moses, Go unto the people, and sanctify them to-day and to-morrow, and let them wash their clothes, and be ready against the third day; for the third day the Lord will come down, in the sight of all the people, upon Mount Sinai.” (Ex. xix. 10.) And thus Maimonides, a great authority in the Jewish Law, says, that ‘Israel was admitted into covenant with God in three ways:—by circumcision, by baptism, (alluding to this command, “Let them wash their clothes,”) and by sacrifice.’ When any of the heathen became proselytes to the Jewish religion, and sought admission into the Jewish church, it is said that the males were circumcised and baptized,—the females were baptized,—and the children generally baptized with the parents. And on the subject of the baptism of heathen children, Maimonides again says, that ‘if an Israelite should find a Gentile infant, and baptize him in the name of a proselyte, behold, he is a proselyte.’
By the precepts relating to ceremonial pollutions, the Jews were rendered incapable of appearing before God in the tabernacle or temple, till they were cleansed either by bathing or sprinkling. In the Nineteenth Chapter of the Book of Numbers the subject is particularly dwelt upon. When any one was ceremonially unclean, it was enjoined, (v. 19,) that a “clean person should sprinkle upon the unclean” (of the water of separation before spoken of) “on the third day, and on the seventh day; and on the seventh day he” (the unclean) was to “purify himself, and wash his clothes and bathe himself in water,” and then he was to be “clean at even. But,” as it is added in the next verse, “the man that shall be unclean, and shall not purify himself, _that soul shall be cut off from among the congregation_, because he hath defiled the Sanctuary of the Lord: the water of separation hath not been sprinkled upon him; he is unclean.”
When Moses received directions from the Lord concerning the consecration of Aaron and his sons, he was commanded (as we read in Ex. xxix. 4,) to “bring them unto the door of the tabernacle of the congregation, and wash them with water;” and then to put the Priestly garments upon them. In short, by the law almost all things were purged by water, as well as by blood;—the one having as distinct and definite a signification as the other. And so familiar and forcible was this figure of water among the Jews, that many of the prophecies and promises relating to the Messiah and the spiritual blessings to be enjoyed in the times of the gospel were couched under it and conveyed by it. By Isaiah it is said of Him, “So shall He _sprinkle_ many nations.” (lii. 15.) And by the prophet Ezekiel the Lord saith,—“Then will I _sprinkle clean water_ upon you, and ye shall be clean: from all your filthiness and from all your idols will I cleanse you. A new heart also will I give you, and a new spirit will I put within you. And I will put my Spirit within you, and cause you to walk in my statutes, and ye shall keep my judgments and do them.” (xxxvi. 25–27.)