Deuteronomy 13:15

15 you must kill with a sword everyone who lives in that city. Destroy the city completely and kill everyone in it, as well as the animals, with a sword.

Deuteronomy 13:15 Meaning and Commentary

Deuteronomy 13:15

Thou shalt surely smite the inhabitants of that city with the
edge of the sword
This could not be the work of a single person, nor of the whole sanhedrim, but was what the whole nation was to join in, according to the above note:

destroying it utterly;
pulling down the houses, and demolishing its walls and fortifications, or burning it, as afterwards explained:

and all that is therein;
men, women, and children:

and the cattle thereof, with the edge of the sword;
this severity was used to show the Lord's indignation against the sin of idolatry, and to deter persons from it, both individuals and bodies of men.

Deuteronomy 13:15 In-Context

13 that evil people have moved in among you. And they might lead the people of that city away from God, saying, "Let's go and worship other gods." (These are gods you have not known.)

14 Then you must ask about it, looking into the matter and checking carefully whether it is true. If it is proved that a hateful thing has happened among you,

15 you must kill with a sword everyone who lives in that city. Destroy the city completely and kill everyone in it, as well as the animals, with a sword.

16 Gather up everything those people owned, and put it in the middle of the city square. Then completely burn the city and everything they owned as a burnt offering to the Lord your God. That city should never be rebuilt; let it be ruined forever.

17 Don't keep for yourselves any of the things found in that city, so the Lord will not be angry anymore. He will give you mercy and feel sorry for you, and he will make your nation grow larger, as he promised to your ancestors.