And king Solomon sent by the hand of Banaias the son of Joiada, who slew him, and he died.

And king Solomon sendeth by the hand of Benaiah son of Jehoiada, and he falleth upon him, and he dieth.

And King Solomon sent Benaiah, the son of Jehoiada, and he made an attack on him and put him to death.

And king Solomon sent by the hand of Benaiah, the son of Jehoiada, who put him to death, and so he died.

Solomon sent - Benaiah - and he fell upon him that he died. - Benaiah seems to have been the public state executioner, and yet he was generalissimo of all the forces. See him employed in a similar work, 1-Kings 2:34 (note), 1-Kings 2:46 (note). I suppose him to have been such another general as Suwarrow, butcher-general of the Turks and Poles to the late Empress Catharine of Russia: like mistress, like man. But they have long since been called to an impartial tribunal.
That this was an act of cruelty towards Adonijah, needs no proof. He is suspected, condemned, and slain, without a hearing. Calmet vindicates all this by various assumptions, and lays down a doctrine that is calculated for the meridian of Fez or Morocco; hear him: Un prince, dans ses jugemens, ne peut pas toujours suivre les regles de la plus parfaite morale; la politique, et le bien de l'etat, obligent souvent a des choses opposees aux conseils de l'evangile; "A prince in his judgments cannot always follow the rules of the most perfect morality; policy and the good of the state often require things to be done which are contrary to the counsels of the Gospel." What a diabolic maxim is this! And is this indeed the way that French kings ruled and ministers decreed judgment? Then we need not wonder at a revolution in that state, nor of the scourge that desolated the land. O England! magnify God for your constitution, your constitutional king, and the laws according to which he reigns.

And King Solomon sent by the hand of Benaiah the son of Jehoiada,.... Orders to execute him, and proper persons to do it; perhaps some of the Cherethites and Pelethites under him, to assist at least in it:
and he fell upon him, that he died; Benaiah rushed in upon him with his men, and thrust his sword into him, and killed him; executions used to be done in those times and countries by great personages, as the instances of Gideon, Doeg, and others, show, and not by common executioners.

Solomon had this sentence immediately executed upon Adonijah by Benaiah, the chief of the body-guard, according to the oriental custom of both ancient and modern times. The king was perfectly just in doing this. For since Adonijah, even after his first attempt to seize upon the throne had been forgiven by Solomon, endeavoured to secure his end by fresh machinations, duty to God, who had exalted Solomon to the throne, demanded that the rebel should be punished with all the severity of the law, without regard to blood-relationship.

Benaiah - For the execution of justice was not then committed to obscure persons, as now it is; but to persons of great honour and authority. It is far from clear, that Solomon did right herein, or that Adonijah had any ill design in asking Abishag.