Deuteronomy 13:9-11, 15-17

You must put them to death. You must be the first one to start to kill them, and then everyone else must join in. You must throw stones at them until they die, because they tried to turn you away from the LORD your God, who brought you out of the land of Egypt, where you were slaves. Then everyone in Israel will hear about this and be afraid, and no one among you will ever do such an evil thing again.

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. 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. 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.