Well, that is what they would like you to believe so that they can heap sexual sins on David that he did not commit, and thus tarnish plural marriage. David sinned in committing adultery with Bathsheba - that was his only sexual sin. But did he marry a daughter and her mother contrary to Leviticus 18:17?
David's first wife was called Michal and her mother was called Ahinoam, the daughter of Ahimaaz (1 Sam.14:49-50). However, the Ahinoam David was married to was a Jezreelite (1 Chr.3:1; 2 Sam.3:2). Moreover, the Ahinoam David married was before Saul, to whom the other Ahinoam belonged, died (2 Sam.3:2; 12:7-8). Saul's wives were given by Yahweh to David after his marriage to Ahinoam so David cannot have been married to Saul's wife of the same name.
Again, the anti-polygamists are clutching at straws.
