Then said Joab to Cushi,.... The Ethiopian, or blackamoor; who either was an Ethiopian by birth and proselyted, or he was an Israelite of a black complexion, and therefore so called; and was judged a proper person by the general to carry such dismal news to the king, as he knew it would be.
Some Jewish writers take him to be the same with Cush the Benjaminite, in the title of the seventh psalm, Ps 7:1; and that he is the same that told Joab he saw Absalom hanging in an oak, and declared that, if a thousand shekels of silver were offered him, he would not have put forth his hand against him, 2Sa 18:10; though some think this was one of the ten young men that waited on Joab, and by his orders slew Absalom; but it would have been dangerous for one of these to have carried the tidings, had he been known by David to have done it:go tell the king what thou hast seen: by which it should seem that he was present when Absalom was killed:and Cushi bowed himself unto Joab; in reverence to him as his general, and in thankfulness for sending him on this errand:and ran; as fast as he could.
Pirke Eliezer, c.