Parah פרה

A heifer without blemish that had never borne a yoke was burned whole outside the city, with cedar, hyssop and crimson thread; the ashes were mixed with spring water and sprinkled on the impure on the third and seventh day. The tractate describes the rite to the smallest detail: where they stood, how it was carried, how the purity of the vessels was guarded.

Tradition calls this law the very model of a "chok"—a commandment without a stated reason, because it contradicts itself: it purifies the impure and defiles the pure. The Mishnah counts how many such heifers were prepared in all of history—and the sages within the tractate disagree about the number.

Order: Tohorot. There is no Gemara in either Talmud—the tractate remained mishnah.