And a pure man shall gather the ashes of the heifer and place them outside the camp in a pure place; and it shall be for the congregation of the children of Yisrael for a keeping, for water of sprinkling; it is a chatas.
Torah Temimah: Sifrei — It teaches that if one altered any of its acts it is invalid; and it teaches that if one slaughtered it not for its own sake it is invalid; and it teaches that it is not burned at night.
English: It teaches that if one altered any of its acts it is invalid; and it teaches that if one slaughtered it not for its own sake it is invalid; and it teaches that it is not burned at night.
Multiple implications from the designation “chatas.”
Because the para is called a “chatas,” any deviation from the prescribed sequence of acts, any shechitah performed not for the sake of the para, or burning performed at night, renders the entire process invalid.