1 Samuel 18:20

But it came to pass at the time when Merab Saul's daughter should have been given to David, that she was given unto Adriel the Meholathite to wife.

And Saul said, I will give him her, that she may be a snare to him, and that the hand of the Philistines may be against him. Wherefore Saul said to David, Thou shalt this day be my son in law in the one of the twain.