17 One day Saul said to David, "Here is Merab, my eldest daughter. I want to give her to you as your wife. Be brave and bold for my sake. Fight God's battles!" But all the time Saul was thinking, "The Philistines will kill him for me. I won't have to lift a hand against him." 18 David, embarrassed, answered, "Do you really mean that? I'm from a family of nobodies! I can't be son-in-law to the king." 19 The wedding day was set, but as the time neared for Merab and David to be married, Saul reneged and married his daughter off to Adriel the Meholathite. 20 Meanwhile, Saul's daughter Michal was in love with David. When Saul was told of this, he rubbed his hands in anticipation. "Ah, a second chance. I'll use Michal as bait to get David out where the Philistines will make short work of him." So again he said to David, "You're going to be my son-in-law." 21
Matthew Henry's Commentary on 1 Samuel 18:17-21
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!