Who told Benaiah to kill Joab?


Solomon

And the king said unto him, Do as he hath said, and fall upon him, and bury him; that thou mayest take away the innocent blood, which Joab shed, from me, and from the house of my father. ...

So Benaiah the son of Jehoiada went up, and fell upon him, and slew him: 1 Kings 2:31-34