וּנְתָנָ֥ם יְהוָ֖ה לִפְנֵיכֶ֑ם וַעֲשִׂיתֶ֣ם לָהֶ֔ם כְּכָל־הַמִּצְוָ֔ה אֲשֶׁ֥ר צִוִּ֖יתִי אֶתְכֶֽם׃
Il mettra ces peuples à votre merci; et vous procéderez à leur égard, en tout, selon l’ordre que je vous ai donné.
Chizkuni
אשר צויתי אתכם, “which I have commanded you.” This is a reference to Deut. 20,16, where G-d had commanded the Jewish people not to allow a single soul of the Canaanites to remain alive, (unless they had left that land of their own accord).
Ibn Ezra
and you will deal with them i.e., to destroy their altars.