1 Samuel 18:17-18

Then Saul said to David, “Here is my older daughter Merab; I will give her to you as a wife, only be a valiant man for me and fight the LORD’S battles.” For Saul thought, “My hand shall not be against him, but let the hand of the Philistines be against him.” But David said to Saul, “Who am I, and what is my life or my father’s family in Israel, that I should be the king’s son-in-law?”