אמור אל הכהנים בני אהרן ואמרת אליהם לנפש לא יטמא בעמיו
And the Lord said to Moses, Speak to the priests, the sons of Aaron, and say to them, There shall be none defiled for the dead among his people (Leviticus 21:1)
In the Midrash (Leviticus Rabbah 26:1) it is written: R. Tanhum son of R. Hannilai opened his discourse with the text (Psalms 12:7), "The words of the Lord are pure" (אמרות ה' אמרות טהורות). Does this mean that only "the words of the Lord are pure words" and the words of mortals are not pure words? It is the way of the world that if a mortal king enters a province and all the citizens of that province praise him, then if their praise is pleasant to him he tells them: "Tomorrow I shall build for you public baths and bathhouses, tomorrow I shall construct a canal for you." Then he falls asleep and does not rise. Where then is he and where are his words? The Holy One Blessed Be He, however, is not so, but The Lord G-d is the true G-d (וה' אלהים אמת) (Jeremiah 10:10). Why is He true? Because, said R. Abin, He is the living G-d, and the everlasting King (שהוא אלהים חיים ומלך עולם) (Id.)
R. Tanhum properly deduced that the promises of the Eternal are pure, i.e. promises that are true and may be depended upon. The promises are called pure, because they come from a pure place and a holy source that is immortal and thus can never become impure. The promises of flesh and blood, however, are not pure and may not be trusted, because their source is a decaying body that must eventually become a dead corpse. The promises of such a being are therefore impure.
However, we must still try to understand why R. Tanhum expounded his words here in connection with this verse. And it appears to our master that R. Tanhum wished to explain why the words "and you shall say" were repeated twice (אמור ואמרת). The word "בעמיו" (among his people), which the Sages understand as a reference to an abandoned corpse (מת מצוה), is also redundant. Thus, R. Tanhum teaches us that since the promises made by human beings are impure, one who relies on human promises defiles his soul with an impurity more severe than that occasioned by entering into a tent in which there is a corpse. Now if a man actually sees his friend and colleague, with whom only yesterday he spoke face-to-face, today being laid to eternal rest, he will draw the appropriate lesson that he should not place his trust in princes whose breath will cease and who will return to dust. But if he does not see this happen with his own eyes, he may not draw that lesson. And this is why the wisest of men said (Eccleisastes 7:2): "It is better to go to the house of mourning than to the house of feasting, for this is the end of all men, and the living will lay it to heart."
Now the priests who have no share in the land and whose eyes are directed for their own support toward the holy offerings of the Children of Israel, their tithes, and their heave-offerings, must be especially careful not to place their trust in human beings and not to be overly regarding of the wealthy. So because the Eternal commanded the priests not to defile themselves by coming into contact with a corpse, they will have no occasion to see a dead person with their own eyes and therefore will be unable to draw from their own experience the lesson that they should not place their confidence in flesh and blood and not depend on a fragile reed. The priests, therefore, are susceptible to an even greater defilement than that of coming into contact with a corpse, which would be to rely on the promises of flesh and blood, thereby incurring a loss greater than their gain. The Scripture therefore repeats the command to speak to the priests (אמור ואמרת) "none of them shall defile himself for the dead" (לנפש לא יטמא). The priests may not permit themselves to be physically defiled through contact with any corpse. But beyond this, they must guard their souls from being defiled "among their people" (בעמיו), by placing their trust in any person still living among their people. And that is why the Midrash for this poroshah begins here with the holy verse "The words of the Lord are pure."
לא יטטא בעל בעמיו להחלו
He shall not defile himself as a husband among his people and so profane himself (Leviticus 21:4).
The Sages deduced that this refers to the prohibited wife of a priest by whom he has been rendered unfit to perform any priestly service. But see the Ibn Ezra who wrote in his commentary that if it were not for the derivation of the Sages, he would have said simply that a priest is not allowed to defile himself even for a legal wife. And he would have explained the verse above (Leviticus 21:2): "except for his nearest of kin" (כי אם לשארו הקרוב אליו) to be a general description that does not include his wife.
But it appears to our master that the derivation of the Sages holds of necessity, because if we were to interpret the verse simply to mean that a priest must not defile himself for his wife whether she be prohibited or permissible, what meaning would we attach to the words "to profane himself" (להחלו)? And even if we interpreted these words, as the Ramban does, to mean that a priest would demean himself in the eyes of the people by involving himself in the burial of his deceased wife, then why were these words not written above, i.e.: "none of them shall defile himself for the dead among his people and so profane himself" (לנפש לא יטמא בעמיו להחלו) instead of here: "he shall not defile himself as a husband and so profane himself" ( לא יטמא בעל בעמיו להחלו)? Moreover, writing "לנפש לא יטמא בעמיו להחלו" would have better indicated that a priest may defile himself for an unclaimed corpse (מת מצוה) than simply writing "בעמיו," inasmuch as it could not be supposed that a priest, by being occupied in the burial of a מת מצוה, would demean himself. We would therefore certainly have known that a priest is enjoined to defile himself for the sake of a מת מצוה. And even the one that holds that we do not deduce any halakhah from the reason for which a commandment was enjoined concedes that, when the Scripture explicitly states the reason for a commandment, we make an inference from an explicit reason. But it is clear that the word "להחלו" was not intended to explain why a priest may not defile himself through contact with a corpse, but rather serves as a reference to a prohibited wife by whom a priest has been profaned.