1 Samuel 18:21

18:21 Saul said, “I will give her to him so that she may become a snare to him and the hand of the Philistines may be against him.” So Saul said to David, “Today is the second time for you to become my son-in-law.”

1 Samuel 18:27

18:27 when David, along with his men, went out and struck down two hundred Philistine men. David brought their foreskins and presented all of them to the king so he could become the king’s son-in-law. Saul then gave him his daughter Michal in marriage.