I Samuel 18:27-30

therefore David arose and went, he and his men, and killed two hundred men of the Philistines. And David brought their foreskins, and they gave them in full count to the king, that he might become the king’s son-in-law. Then Saul gave him Michal his daughter as a wife. Thus Saul saw and knew that the LORD was with David, and that Michal, Saul’s daughter, loved him; and Saul was still more afraid of David. So Saul became David’s enemy continually. Then the princes of the Philistines went out to war. And so it was, whenever they went out, that David behaved more wisely than all the servants of Saul, so that his name became highly esteemed.