This week's section discusses the Red Heifer. One of the procedures involved was taking the ashes of this heifer, mixing them with water, and sprinkling it a number of times on a person to purify them from the impurity of touching a corpse. These ashes were divided into three parts: 1) one part to purify people impure with the impurity of the dead; 2) another part to purify the kohanim - priests - who would make the next red cows and 3) another part to keep it." What is the use of the third part?
To understand this, we must first grasp the eternal, timeless, and placeless spiritual significance of the red heifer. The Torah states that, to prepare the ashes of the red heifer, Cohen He must leave the camp, and by burning the cow's carcass and preparing the ashes, he defiles himself. From this we can learn a timeless lesson of love for our neighbor and concern for others.
When we see a Jew whose connection to the Living God is clearly not recognized, we might think that if he has fallen to such a low level, he is already lost (God forbid). That is why the Torah says that Moses gave us the power to purify every Jew, even one who is at the lowest spiritual level, at the level of "dead impurity.".
The Inclination to Evil may continue to argue that even if we claim to have the power to purify and save him, why is it our responsibility to descend to such a low level, to the point of risking impurity ourselves? Should a person harm themselves spiritually for the sake of their neighbor?
The Torah says, "This is the rule of the Torah." This phrase expresses the entire essence of the Torah: one must sacrifice oneself for another Jew and help him purify himself, even if it means leaving the camp and becoming ritually impure. When a person sets himself aside for another Jew, he reveals the essence of his own soul, which transcends impurity.
However, there is still a concern that a person who sees that they are successful in influencing others might think that this success stems from their own powers—"My strength and the power of my hands granted me this level." That is why Moshe left ashes to purify the kohanim that the next red heifers would do, so that the one who purifies others may know and remember that he does not do this by his own strength, but by the strength of Moshe.
And even with all this, it is not enough, because one can become so involved in community tasks and helping others that one forgets oneself and one's position in relation to serving God. That is why Moses left a third portion to "keep" for oneself. A person must remember that he too can find himself in a state of "uncleanness of the dead," God forbid, for which he will need the ashes of the red heifer.
This combination of selflessness and concern for one's own well-being is the great innovation of the Torah. On the one hand, we must act for the sake of our neighbor—"when you see him naked, you shall cover him." When we see a Jew "naked" of mitzvot, we should be concerned that he observes mitzvot, that he wears them. Tefillin and view Tzitzit. On the other hand, as the verse continues, "and do not hide yourself from your own flesh." We must remember that we ourselves are "flesh," and fatty, materialistic flesh that must be washed, salted, and rinsed. This combination is what brings true purity, even the complete purity of Redemption.
Extracted from www.chabad.org.il