Aside from the mitzvah of the red heifer “requiring” the revelation of Mashiach (as mentioned above, end of Section 3), the content of the mitzvah itself is connected to the Redemption.
A comparable example appears in Rashi’s Torah commentary (explaining the plain meaning of Scripture): “These are the offspring of Noach — Noach was a righteous man” (beginning of parshas Noach), where Rashi notes: “Since {Scripture} mentioned him, it spoke of his praise, as it says, (Mishlei 10:7) ‘The mention of a righteous person is for a blessing.’” Nevertheless, we don’t find that the Torah “spoke of his praise” everytime a righteous person is mentioned! The obvious explanation is that the Torah’s intention (the word Torah is etymologically related to the word hora’ah, meaning instruction) is to teach us this practice, for which a single instance suffices. This is self-evident.
Regarding why Rambam teaches this halacha specifically in Hilchos Parah Adumah (rather than at Mashiach’s first mention in Mishneh Torah): he selected a section that has a substantive connection {to Mashiach}, as explained below in Section 6.
Exile, in a general sense, is a state of impurity from a corpse. Beyond the literal fact that we are impure from corpses, this also describes the spiritual experience of exile: Exile is caused by “our sins,” when there is a deficiency in “But you who cling to Hashem, your G-d,” automatically leading to a deficiency in “you are all alive today.”
And the ashes of the red heifer, the purification from this impurity, symbolizes the redemption from exile, the purification from a state of separation from our bond with Hashem, the G-d of Life.
We can posit that this is the precise implication of the prophecy of redemption, “I will sprinkle pure waters upon you, and you shall be pure,” where the verse uses the word “sprinkle” specifically, meaning that the purification comes through sprinkling — “the sprinkling of the purifying waters which remove the defilement caused by a corpse.” This purification will be openly manifest with the arrival of our righteous Mashiach —
— may he come and redeem us speedily in our days, and in Rambams’s words, “may he speedily be revealed. Amen, so may it be Hashem’s will!”
— From a talk delivered on the 7th of Mar Cheshvan, 5746 (1985)
References
Rashi on Yechezkel there; Chiddushei Aggados Maharsha on Yoma 85b; see also Likkutei Sichos, vol. 17 (p. 179 and p. 184) — talks celebrating the completion of tractate Yoma.
Yechezkel 36:25.
Devarim 4:4; see Avos d’Rabbi Nasan, ch. 34, par. 10.
And in many areas, the dictum “What is it to me if he killed it entirely, what is it to me if he killed it partially?” applies (Bava Kama 65a; Bava Metzia 95a; Chulin 35b; and the sources listed there).
Echoing the expression “we are all impure from a corpse” (wording of Yere’im, sec. 325 [in Yere’im Hashalem, sec. 277]; Radvaz on Hilchos Bikurim, ch. 5, par. 9; Bach on Shulchan Aruch, “Yoreh Deah,” sec. 322; Magen Avraham, sec. 561, par. 2; et al). See also Tur, “Yoreh Deah,” sec. 311: “everyone is impure”; Raavad, “Hilchos Nezirus” (ch. 5, par. 15-17): “and the Kohanim nowadays are impure from a corpse”; and other sources. See further Encyclopedia Talmudis, end of entry “eifer parah” (and the sources listed there); et al.
