(Exodus 22:19 NAB) They entered into a covenant to seek the Lord, the God of their fathers, with all their heart and soul; and everyone who would not seek the Lord, the God of Israel, was to be put to death, whether small or great, whether man or woman.
(2 Chronicles 15:12-13 NAB) Suppose you hear in one of the towns the LORD your God is giving you that some worthless rabble among you have led their fellow citizens astray by encouraging them to worship foreign gods. In such cases, you must examine the facts carefully. If you find it is true and can prove that such a detestable act has occurred among you, you must attack that town and completely destroy all its inhabitants, as well as all the livestock.
(Deuteronomy 13:13-19 NLT) If your own full brother, or your son or daughter, or your beloved wife, or you intimate friend, entices you secretly to serve other gods, whom you and your fathers have not known, gods of any other nations, near at hand or far away, from one end of the earth to the other: do not yield to him or listen to him, nor look with pity upon him, to spare or shield him, but kill him.