Why did David, a faithful servant of Jehovah, allow his wife Michal to have a teraphim image, or idol, as indicated at 1 Samuel 19:12, 13?

First, let us briefly consider the context. When news of King Saul’s plot to kill David reached David’s wife, she responded immediately. The Bible says: “Michal had David descend through the window, that he might go and run away and escape. Then Michal took the teraphim image [which was evidently the size and shape of a man] and placed it on the couch, and a net of goats’ hair she put at the place of his head, after which she covered it with a garment.” When the messengers of Saul came to seize David, Michal told them: “He is sick.” 


This ploy bought valuable time, and David made good his escape.—1 Samuel 19:11-16.
Archaeological findings suggest that in ancient times, teraphim images were kept not only for religious use but also for legal purposes. Just as title deeds and written testaments determine inheritance rights today, so did teraphim images long ago. Evidently, the possession of the teraphim could, under certain circumstances, give a son-in-law the right to claim the estate of his deceased father-in-law. This may explain why, on an earlier occasion, Rachel took her father’s teraphim images and why he was so anxious to recover them. In that instance, Rachel’s husband, Jacob, was unaware of what his wife had done.—Genesis 31:14-34.


When the Israelites became a nation, they received the Ten Commandments, the second of which specifically prohibits the making of idols. (Exodus 20:4, 5) Later, the prophet Samuel alluded to this law in speaking to King Saul. He said: “Rebelliousness is the same as the sin of divination, and pushing ahead presumptuously the same as using uncanny power and teraphim.” (1 Samuel 15:23) For this reason, it is not likely that the teraphim served for purposes of inheritance in Israel. Nonetheless, this ancient form of Jewish superstition appears to have continued in some Israelite households. (Judges 17:5, 6; 2 Kings 23:24) That Michal kept a teraphim image among her possessions suggests that her heart was not complete with Jehovah. David either did not know about the teraphim image or tolerated it because Michal was the daughter of King Saul.


David’s view of exclusive devotion to Jehovah is expressed in the words: “Jehovah is great and very much to be praised, and he is to be feared more than all other gods. For all the gods of the peoples are valueless gods. As for Jehovah, he made the heavens.”—1 Chronicles 16:25, 26.