21 She said, "Let Ab'ishag the Shu'nammite be given to Adoni'jah your brother as his wife." 22 King Solomon answered his mother, "And why do you ask Ab'ishag the Shu'nammite for Adoni'jah? Ask for him the kingdom also; for he is my elder brother, and on his side are Abi'athar the priest and Jo'ab the son of Zeru'iah." 23 Then King Solomon swore by the Lord, saying, "God do so to me and more also if this word does not cost Adoni'jah his life! 24 Now 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, Adoni'jah shall be put to death this day." 25 So King Solomon sent Benai'ah the son of Jehoi'ada; and he struck him down, and he died.
Matthew Henry's Commentary on 1 Kings 2:21-25
Commentary on 1 Kings 2:12-25
(Read 1 Kings 2:12-25)
Solomon received Bathsheba with all the respect that was owing to a mother; but let none be asked for that which they ought not to grant. It ill becomes a good man to prefer a bad request, or to appear in a bad cause. According to eastern customs it was plain that Adonijah sought to be king, by his asking for Abishag as his wife, and Solomon could not be safe while he lived. Ambitious, turbulent spirits commonly prepare death for themselves. Many a head has been lost by catching at a crown.