Cush was the father of Nimrod, who established himself as a mighty warrior on earth. ¹ 

Abishai the brother of Joab was head of the three ¹  elite warriors. He killed three hundred men with his spear ²  and gained fame along with the three elite warriors. ³ 

The sons of Reuben, Israel’s firstborn – (Now he was the firstborn, but when he defiled his father’s bed, ¹  his rights as firstborn were given to the sons of Joseph, Israel’s son. So Reuben is not listed as firstborn in the genealogical records. ² 

Joab son of Zeruiah started to count the men but did not finish. God was angry with Israel ¹  because of this, so the number was not recorded in the scroll ²  called The Annals of King David.