'Son in law' in the Bible

But David said to Saul, “Who am I, and what is my life or my father’s family in Israel, that I should be the king’s son-in-law?”

Saul thought, “I will give her to him that she may become a snare to him, and that the hand of the Philistines may be against him.” Therefore Saul said to David, “For a second time you may be my son-in-law today.”

Then Saul commanded his servants, “Speak to David secretly, saying, ‘Behold, the king delights in you, and all his servants love you; now therefore, become the king’s son-in-law.’”

So Saul’s servants spoke these words to David. But David said, “Is it trivial in your sight to become the king’s son-in-law, since I am a poor man and lightly esteemed?”

When his servants told David these words, it pleased David to become the king’s son-in-law. Before the days had expired

David rose up and went, he and his men, and struck down two hundred men among the Philistines. Then David brought their foreskins, and they gave them in full number to the king, that he might become the king’s son-in-law. So Saul gave him Michal his daughter for a wife.

Then Ahimelech answered the king and said, “And who among all your servants is as faithful as David, even the king’s son-in-law, who is captain over your guard, and is honored in your house?