The Torah in the beginning of the Sidra presents the laws of the פָרָה אֲדֻמָּה, the Red Heifer. This is a special law that requires a heifer, that is completely red, to be taken, sacrificed and burnt. The ashes were to be mixed with water and the mixture was to be used to sprinkle on one who has become טמא or spiritually contaminated, having come in contact with a deceased body.
This is the least understood Mitzvah in the entire Torah. The Torah calls this a חוק, a statute, which implies a Mitzvah for which we have no understanding. The Midrash tells us that even King Solomon, the wisest of all men, had no explanation for this Mitzvah.
The Torah Portion starts with the words: זֹאת חֻקַּת הַתּוֹרָה, “This is the statute of the Torah…” (Num. 19,2) Many of the Biblical commentaries ask, “Why is the wording the statute of the Torah?” It should have said, “the statute of the Red Heifer”.
Someone proposed a unique answer for this question. There are two types of Mitzvot. There are those that we can readily understand. For example, the prohibition against stealing and the Mitzvah to give charity are Mitzvot we can explain. There are other Mitzvot for which we have no rationalization. An example of this would be טומאה, spiritual defilement.
If one observes the Mitzvot he does not understand, we would assume his reward would be greater than when he observes the Mitzvot he can explain. Hence, the Torah emphasizes here that one who observes the law of the Red Heifer demonstrates that he fulfills Mitzvot, not because he understands them, but because it is the command of Hashem. Thus, the rewards for even the Mitzvot he does understand will be as great because he practices them, not because they are logical, but because they are Hashem’s command.
That is why the Torah says: “This is the statute of the Torah…”. It implies that observing this Mitzvah is an indication that all Mitzvot of the Torah are observed because they are divine and not because they are rational.