Then Saul said to David, “Here is my oldest daughter Merab, I will give her to you as a wife. Only be a son of valor for me and fight Yahweh’s battles.” For Saul said
to himself, “Let not my hand be on him, but let the hand of the Philistines be on him.”

“son of valor.” A “son of valor” was a Semitic way of saying a valiant man.