1 Kings 2:23-25

23Then King Solomon swore by the Lord, saying, “May God do the same to me, and more also, if Adonijah has not requested this [deplorable] thing against his own life.

24So now, as the Lord lives, who has established me and set me on the throne of David my father, and who has made me a house as He promised, Adonijah shall indeed be put to death today.”

25So King Solomon sent Benaiah the son of Jehoiada, and he struck Adonijah and he died.