Commentaire sur Le Deutéronome 12:2

אבד תאבדון YE SHALL UTTERLY DESTROY — Destroy and again destroy! (i.e. utterly destroy). From here we learn that he who eradicates an object of idol-worship must thoroughly uproot it (i.e. remove every trace of it) (Sifrei Devarim 60:1).

אבד תאבדון את כל המקמזת, "You shall utterly destroy all the sites, etc." We can understand this verse in conjunction with the Mishnah 7 chapter 3 in tractate Avodah Zarah. We are taught there: "there are three categories of houses; 1) a house which was constructed in order to serve as a place of worship. Such a house is (totally) forbidden. 2) A house which originally was not used or intended for such worship but has been redecorated in order to serve as a house of worship. 3) The Gentile made an addition to the existing house which was intended and used as a residence. In the latter two instances the Jew has to demolish all the new decorations or additions and he may have use of the rest of such a house." The Talmud elaborates on this Mishnah saying that if someone prostrates himself in front of any house (indicating he worships it) he has thereby made it completely forbidden to every Jew. From this we deduce that even if someone had only joined together individual stones and attached them to the ground they are still considered as if they were separate and the house is not forbidden until it was used for the purpose for which it has been designated! The Talmud queries why this should be so seeing the Mishnah had forbidden such a house even if the entire house had been built for an idolatrous purpose before anyone had prostrated himself! The Talmud answers that the Mishnah taught us the law that even if the house had only been built for a purpose for which it had not yet been used it is already totally forbidden. Thus far the Talmud on the subject. Maimonides accepts this ruling in his treatise Hilchot Avodah Zarah chapter 8. This ruling is reflected in what our verse says: "all the sites where the Canaanites used to serve idols." The meaning is that it is irrelevant if the place had originally been built for the purpose or not. If idolatrous practices had been performed there the Israelites must destroy it even if only an addition to such a house had been used for idolatry.

אשר עבדו שם הגויים, where the former inhabitants worshipped their deities.