1 Kings 2:21-25

21She said, "Let Abishag the Shunammite be given to Adonijah your brother as his wife."

22King Solomon answered his mother, "And why do you ask Abishag the Shunammite for Adonijah? Ask for him the kingdom also, for he is my older brother, and on his side are Abiathar the priest and Joab the son of Zeruiah."

23Then King Solomon swore by the Lord, saying, "God do so to me and more also if this word does not cost Adonijah his life!

24Now therefore as the Lord lives, who has established me and placed me on the throne of David my father, and who has made me a house, as he promised, Adonijah shall be put to death today."

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