2 Samuel 3:13

Except thou first bring Michal. Besides David's affection for Michal, there were political reasons for demanding her restoration. Saul's despotic act in giving her in marriage to another man ( 1 Samuel 25:44 ) had been a public disavowal of David as the son-in-law of the royal house, and equivalent to a proclamation of outlawry. David's rights were all declared null by such an act. But now Ishbosheth must with equal publicity reverse his father's deed, and restore to David his lost position. It must have been a most painful humiliation to him to be driven thus to cancel his father's decree, and declare thereby to all Israel that he was unable to refuse hie assent to whatever his rival demanded. And for this reason David sent his messengers directly to Ishbosheth, because the importance of Michal's surrender to him lay in its being a public act of the state. For Michal, in 2 Samuel 21:8 , we ought to read Merab (see note there).