1 Samuel 18:28 (KJV)

And Saul's servants spake those words in the ears of David. And David said, Seemeth it to you a light thing to be a king's son in law, seeing that I am a poor man, and lightly esteemed?

And the servants of Saul told him, saying, On this manner spake David.

And Saul said, Thus shall ye say to David, The king desireth not any dowry, but an hundred foreskins of the Philistines, to be avenged of the king's enemies. But Saul thought to make David fall by the hand of the Philistines.

And when his servants told David these words, it pleased David well to be the king's son in law: and the days were not expired.

Wherefore David arose and went, he and his men, and slew of the Philistines two hundred men; and David brought their foreskins, and they gave them in full tale to the king, that he might be the king's son in law. And Saul gave him Michal his daughter to wife.

And Saul was yet the more afraid of David; and Saul became David's enemy continually.

Then the princes of the Philistines went forth: and it came to pass, after they went forth, that David behaved himself more wisely than all the servants of Saul; so that his name was much set by.