'Son in law' in the Bible

David said to Saul, "Who am I? Who are my relatives or the clan of my father in Israel that I should become the king's son-in-law?"

Saul said, "I will give her to him so that she may become a snare to him and the hand of the Philistines may be against him." So Saul said to David, "Today is the second time for you to become my son-in-law."

Then Saul instructed his servants, "Tell David secretly, 'The king is pleased with you, and all his servants like you. So now become the king's son-in-law."

So Saul's servants spoke these words privately to David. David replied, "Is becoming the king's son-in-law something insignificant to you? I'm just a poor and lightly-esteemed man!"

So his servants told David these things and David agreed to become the king's son-in-law. Now the specified time had not yet expired

when David, along with his men, went out and struck down two hundred Philistine men. David brought their foreskins and presented all of them to the king so he could become the king's son-in-law. Saul then gave him his daughter Michal in marriage.

Ahimelech replied to the king, "Who among all your servants is faithful like David? He is the king's son-in-law, the leader of your bodyguard, and honored in your house!