The total destruction of these Canaanite cities is based on the herem principle. This principle refers to the irrevocable giving over of things or persons to the Lord.1 Sometimes it indicates that someone or something has been set apart for service or use in the sanctuary (Leviticus 27:28; Micah 4:13). However, in the context of cities, it refers to the complete annihilation of a place and its people. As God’s instrument of judgment upon the people of Canaan (Genesis 15:16), the Lord instructed the people of Israel through Moses that they were to destroy certain cities and populations in the land of Canaan (Numbers 21:2–3; Deuteronomy 7:2; Deuteronomy 9:5; Deuteronomy 13:15; Deuteronomy 20:17). Joshua was charged with carrying out these instructions and that is what he is doing in verses 28–40.
Complete destruction of the city implies that everyone was killed, including animals (Joshua 6:21).2
28 As for Makkedah, Joshua captured it on that day and struck it, and its king, with the edge of the sword. He devoted to destruction every person in it; he left none remaining. And he did to the king of Makkedah just as he had done to the king of Jericho.