2Sam 3:12-13

12Abner sent messengers to David at Hebron, saying, “To whom does the land belong? Make your covenant with me, and I will give you my support to bring all Israel over to you.”13He said, “Good; I will make a covenant with you. But one thing I require of you: you shall never appear in my presence unless you bring Saul's daughter Michal when you come to see me.”