Deuteronomy 13:6-9

6“If your brother, the son of your mother, your son or your daughter, the wife of your bosom, or your friend who is as your own soul, secretly entices you, saying, ‘Let us go and serve other gods,’ which you have not known, neither you nor your fathers,

7of the gods of the people which are all around you, near to you or far off from you, from one end of the earth to the other end of the earth,

8you shall not consent to him or listen to him, nor shall your eye pity him, nor shall you spare him or conceal him;

9but you shall surely kill him; your hand shall be first against him to put him to death, and afterward the hand of all the people.