21 And she said, Let Abishag the Shunammite be given to Adonijah your brother for a wife. 22 Then King Solomon made answer and said to his mother, Why are you requesting me to give Abishag the Shunammite to Adonijah? Take the kingdom for him in addition, for he is my older brother, and Abiathar the priest and Joab, the son of Zeruiah, are on his side. 23 Then King Solomon took an oath by the Lord, saying, May God's punishment be on me if Adonijah does not give payment for these words with his life. 24 Now by the living Lord, who has given me my place on the seat of David my father, and made me one of a line of kings, as he gave me his word, truly Adonijah will be put to death this day. 25 And King Solomon sent Benaiah, the son of Jehoiada, and he made an attack on him and put him to death.
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.