20 Now Michal, Saul's daughter, loved David. And they told Saul, and the thing pleased him. 21 So Saul said, "I will give her to him, that she may be a snare to him, and that the hand of the Philistines may be against him." Therefore Saul said to David a second time, "You shall be my son-in-law today." 22 And Saul commanded his servants, "Communicate with David secretly, and say, 'Look, the king has delight in you, and all his servants love you. Now therefore, become the king's son-in-law.' " 23 So Saul's servants spoke those words in the hearing of David. And David said, "Does it seem to you a light thing to be a king's son-in-law, seeing I am a poor and lightly esteemed man?" 24 And the servants of Saul told him, saying, "In this manner David spoke." 25 Then Saul said, "Thus you shall say to David: 'The king does not desire any dowry but one hundred foreskins of the Philistines, to take vengeance on the king's enemies.' " But Saul thought to make David fall by the hand of the Philistines. 26 So when his servants told David these words, it pleased David well to become the king's son-in-law. Now the days had not expired; 27 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.
Matthew Henry's Commentary on 1 Samuel 18:20-27
Commentary on 1 Samuel 18:12-30
(Read 1 Samuel 18:12-30)
For a long time David was kept in continual apprehension of falling by the hand of Saul, yet he persevered in meek and respectful behaviour towards his persecutor. How uncommon is such prudence and discretion, especially under insults and provocations! Let us inquire if we imitate this part of the exemplary character before us. Are we behaving wisely in all our ways? Is there no sinful omission, no rashness of spirit, nothing wrong in our conduct? Opposition and perverseness in others, will not excuse wrong tempers in us, but should increase our care, and attention to the duties of our station. Consider Him that endured contradiction of sinners against himself, lest ye be weary and faint in your minds, Hebrews 12:3. If David magnified the honour of being son-in-law to king Saul, how should we magnify the honour of being sons to the King of kings!