Parah, Chapter 3, Mishnah 10. This chapter follows the burning of the parah adumah step by step, and here we reach the moment when the three items that the Torah requires be thrown into the fire are brought forward and displayed before everyone present.
"Nivke'ah": when the animal burst open from the heat of the flames, the kohen left the pit in which she lay burning and took up a position just alongside it, as the Mishnah puts it, "ve'amad chutz migisah." There he gathers into his hands the three additional ingredients: "notal," he takes, "eitz erez," a piece of cedar, "ezov," a sprig of hyssop, and "shni tolas," wool colored crimson.
Now comes the public questioning. "Amar lahen": he addresses the people standing by, asking first, "eitz erez zeh?", and again, "eitz erez zeh?"; then, "ezov zeh?", and once more, "ezov zeh?"; and finally about the dyed wool: is this the shni tolas? Is this the shni tolas? Every single one of the three, the Mishnah records, was raised as a question "shalosh pe'amim," three times over, "al kol davar ve'davar." And their reply is recorded as well, "veheim omrim lo": they told him "hein," yes, and yes again, so that each of the three materials received its confirmation on three separate occasions.
Why three times?
The threefold questioning is not mere ceremony. There are seven different species that go by the name of cedar, and four different plants that are called hyssop, so that identifying the correct one is a genuine halachic determination. The crimson dye too can come from more than one source: some produce it from the madder plant, whose root yields a reddish color, some from sealing wax, and some from the tolas worm itself, which is the material the Torah intends. Since each of the three items could easily be confused with something that merely resembles it, the kohen holds it up and declares it publicly, so that all present can confirm that what is about to be cast into the fire is precisely what the Torah specified.
Asking permission of Beis Din
There is a further dimension to his question. He is not only verifying the identity of the materials; he is requesting authorization from the Beis Din before proceeding. In effect he asks: Shall I cast in this cedar wood? Shall I cast in this hyssop? Shall I cast in this crimson wool? Nothing in this avodah is done on the kohen's own initiative alone.
The Tosefta records that this too was said in the same triple pattern: the kohen would ask, Shall I cast it in? Shall I cast it in? Shall I cast it in? And they would answer him, Yes, yes, yes. Every stage of the parah adumah is carried out under open, repeated public confirmation, leaving no room for error in the ingredients or in the authorization to use them.