The same interpretation is given in Sifra of the words, "Ye shall be holy, "i.e. obedient to His commandments (xix. 2). Hence the transgression of commandments is also called uncleanliness or defilement. This term is especially used of the chief and principal crimes, which are idolatry, adultery, and murder. In reference to idolatry it is said, "He hath given of his seed unto Molech to defile my sanctuary, and to profane my holy name" (ibid. xx. 3). In reference to adultery we read, "Defile not ye yourselves in any of these things" (ibid. xviii. 24), and Defile not the land" (Num. xxxv. 34) in reference to murder. It is therefore clear that the term "defilement" [or uncleanliness] is used homonymously of three things: 1. Of man's violation and transgression of that which he is commanded as regards his actions and his opinions. 2. Of dirt and filth: comp. "Her filthiness in her skirts" (Lam. i. 9). 3. Of the above-named imaginary defilement such as touching and carrying certain objects, or being with them under the same roof. In reference to the third kind, our Sages said, The words of the Law are not subject to becoming unclean (B. T. Ber. 224). In the same manner the term "holiness" is used homonymously of three things corresponding to the three kinds of uncleanness. As uncleanness caused by a dead body could only be removed after seven days, by means of the ashes of the red heifer, and the priests had constantly occasion to enter the Sanctuary, the Law exceptionally forbids them to defile themselves by a dead body (Lev. xxi. 1), except in cases where defilement is necessary, and the contrary would be unnatural. For it would be unnatural to abstain from approaching the dead body of a parent, child, or brother. As it was very necessary that the high-priest should always be in the Sanctuary, in accordance with the Divine command, "And it shall always be on his forehead" (Exod. xxviii. 38), he was not permitted to defile himself by any dead body whatever, even of the above-named relatives (Lev. xxi. 10-12). Women were not engaged in sacrificial service; the above law consequently does not apply to women; it is addressed to "the sons of Aaron," and not to "the daughters of Aaron." It was, however, impossible to assume that none of the Israelites made a mistake, by entering the Sanctuary, or eating hallowed things in a state of uncleanliness. It was even possible that there were persons who did this knowingly, since there are wicked people who commit knowingly even the greatest crimes; for this reason certain sacrifices were commanded as an atonement for the defilement of the Sanctuary and its hallowed things. They were of different kinds; some of them atoned for defilement caused ignorantly, others for defilement caused knowingly. For this purpose were brought the goats on the Festivals and the New-moon days (Num. xxviii. 15, 27, etc.), and the goat sent away on the Day of Atonement (Lev. xvi. 16), as is explained in its place (Mishnah Shebnot, i. 4). These sacrifices serve to prevent those who defiled the Sanctuary of the Lord knowingly from thinking that they had not done a great wrong; they should know that they obtained atonement by the sacrifice of the goat, as the Law says, "That they die not in their uncleanness" (Lev. xv. 31); "That Aaron may bear the iniquity of the holy things" (Exod. xxviii. 38). This idea is frequently repeated.
The uncleanness through leprosy we have already explained. Our Sages have also clearly stated the meaning thereof. All agree that leprosy is a punishment