וְהָיָ֞ה כְּתָפְשְׂכֶ֣ם אֶת־הָעִ֗יר תַּצִּ֤יתוּ אֶת־הָעִיר֙ בָּאֵ֔שׁ כִּדְבַ֥ר יְהוָ֖ה תַּעֲשׂ֑וּ רְא֖וּ צִוִּ֥יתִי אֶתְכֶֽם׃
And it shall be, when ye have seized upon the city, that ye shall set the city on fire; according to the word of the LORD shall ye do; see, I have commanded you.’
Read midrashic interpretation of Joshua 8:8: and classical rabbinic exegesis.