1 Kings 2:24 (KJV)

And king Solomon answered and said unto his mother, And why dost thou ask Abishag the Shunammite for Adonijah? ask for him the kingdom also; for he is mine elder brother; even for him, and for Abiathar the priest, and for Joab the son of Zeruiah.

Then king Solomon sware by the Lord, saying, God do so to me, and more also, if Adonijah have not spoken this word against his own life.

Now therefore, as the Lord liveth, which hath established me, and set me on the throne of David my father, and who hath made me an house, as he promised, Adonijah shall be put to death this day.

And king Solomon sent by the hand of Benaiah the son of Jehoiada; and he fell upon him that he died.

And unto Abiathar the priest said the king, Get thee to Anathoth, unto thine own fields; for thou art worthy of death: but I will not at this time put thee to death, because thou barest the ark of the Lord God before David my father, and because thou hast been afflicted in all wherein my father was afflicted.