Study
18 and Benaiah son of Jehoiada [is over] both the Cherethite and the Pelethite, and the sons of David have been ministers.
'Edom' or 'Idumea,' as in Isaiah 34:5, signifies people who are in evil and falsities derived there.
(Notae: The Inner Meaning of the Prophets and Psalms 34)
5 For my sword has drunk its fill in the sky. Behold, it will come down on Edom, and on the people of my curse, for judgment.