"with stones": I might think with many stones; it is, therefore, written (Vayikra 20:27) "with a stone." If "with a stone," I might think even with one stone. It is, therefore, written "with stones." Say, then, (that the meaning is) if she does not die with the first stone, she dies with the second.
"for she has done a vile thing in Israel": She has vilified not only herself, but all the virgins of Israel.
"to harlotize the house of her father." It is written here, "her father," and, elsewhere (Ibid. 21:9), "And the (betrothed or married) daughter of a Cohein, if she profane herself through fornication, she profanes her father": Just as there, (Scripture speaks of) harlotry in the context of marriage (and not in that of a single girl); here, too, harlotry in the context of marriage.