Albert Barnes Commentary 2 Samuel 3:13

"And he said, Well; I will make a league with thee; but one thing I require of thee: that is, thou shalt not see my face, except thou first bring Michal, Saul`s daughter, when thou comest to see my face." — 2 Samuel 3:13 (ASV)

David’s motive in requiring the return of Michal was partly his affection for her and his memory of her love for him; partly the wish to wipe out the affront of having his wife taken from him; and partly, also, a political consideration of the effect on Saul’s partisans of having a daughter of Saul as his queen.