1 Samuel 18:21-22, 29

Saul said, “I will give her to him so that she may become a snare (bad influence, source of trouble) to him, and that the hand of the Philistines may be against him.” So Saul said to David for a second time, “You shall be my son-in-law today.” Then Saul commanded his servants, “Speak to David secretly, saying, ‘Listen, the king delights in you, and all his servants love you; now then, become the king’s son-in-law.’ ”

Saul was even more afraid of David; and Saul became David’s constant enemy.