If your very own brother, or your son or daughter, or the wife you love, or your closest friend secretly entices you, saying, "Let us go and worship other gods" (gods that neither you nor your fathers have known, gods of the peoples around you, whether near or far, from one end of the land to the other), do not yield to him or listen to him. Show him no pity. Do not spare him or shield him. You must certainly put him to death. Your hand must be the first in putting him to death, and then the hands of all the people.
--Deuteronomy 13:6-9
If you hear it said about one of the towns the LORD your God is giving you to live in that wicked men have arisen among you and have led the people of their town astray, saying, "Let us go and worship other gods" (gods you have not known), then you must inquire, probe and investigate it thoroughly. And if it is true and it has been proved that this detestable thing has been done among you, you must certainly put to the sword all who live in that town. Destroy it completely, both its people and its livestock.
--Deuteronomy 13:12-15
Wherefore David arose and went, he and his men, and slew of the Philistines two hundred men; and David brought their foreskins, and they gave them in full tale to the king, that he might be the king's son in law. And Saul gave him Michal his daughter to wife.
--1 Samuel 18:27
Whoever is captured will be thrust through; all who are caught will fall by the sword. Their infants will be dashed to pieces before their eyes; their houses will be looted and their wives ravished.
--Isaiah 13:15-16