Solomon was the new, and rightful, King of Judah. Adonijah, his older brother, had already attempted the abscond with the heritage he had desired in heart (with an agenda) for such a long time. When that had been aborted and came to a halt, Adonijah responded with treachery, by asking "innocently" that Bathsheba, the favorite of David, and Solomon's Mother, to speak in his behalf with Solomon, the Heir of King David, to marry the one person, Abishag, who had heard the discussion between David and Bathsheba concerning who was the chosen and rightful heir to David's throne. That was clearly Solomon, and had Adonijah been permitted to marry Abishag, he then could also demand her loyalty and her silence on any accord, thus creating reasonable doubt for Adonijah, as to Solomon's claim to the throne. In this time and age, the King had the authority of a Judge and Jury, thus when he asked one of the inner circle of 30 Men, very loyal men to King David, and now Solomon, to carrry out the sentence of death on Adonijah, Benaiah, he was just assigning the duty to Benaiah to execute Adonijah. Solomon was eliminating Adonijah's agenda by the best legal method available, The standard method of then.
Solomon was the new, and rightful, King of Judah. Adonijah, his older brother, had already attempted the abscond with the heritage he had desired in heart (with an agenda) for such a long time. When that had been aborted and came to a halt, Adonijah responded with treachery, by asking "innocently" that Bathsheba, the favorite of David, and Solomon's Mother, to speak in his behalf with Solomon, the Heir of King David, to marry the one person, Abishag, who had heard the discussion between David and Bathsheba concerning who was the chosen and rightful heir to David's throne. That was clearly Solomon, and had Adonijah been permitted to marry Abishag, he then could also demand her loyalty and her silence on any accord, thus creating reasonable doubt for Adonijah, as to Solomon's claim to the throne. In this time and age, the King had the authority of a Judge and Jury, thus when he asked one of the inner circle of 30 Men, very loyal men to King David, and now Solomon, to carrry out the sentence of death on Adonijah, Benaiah, he was just assigning the duty to Benaiah to execute Adonijah. Solomon was eliminating Adonijah's agenda by the best legal method available, The standard method of then.