2 Samuel 3:12-13

12Then Abner sent messengers on his behalf to say to David, “To whom does the land belong? Make your covenant with me, and surely my hand will be with you to bring all Israel over to you.”

13“Good,” replied David, “I will make a covenant with you. But there is one thing I require of you: Do not appear before me unless you bring Saul’s daughter Michal when you come to see me.”