Joab's brother Abishai (their mother was Zeruiah) was the leader of “The Famous Thirty.” He fought with his spear against three hundred men and killed them, and became famous among “The Thirty.”
When the Ammonites saw the Syrians running away, they fled from Abishai and retreated into the city. Then Joab turned back from fighting the Ammonites and went back to Jerusalem.
Then he sent them out in three groups, with Joab and Joab's brother Abishai and Ittai from Gath, each in command of a group. And the king said to his men, “I will go with you myself.”
Amasa was not on guard against the sword that Joab was holding in his other hand, and Joab stabbed him in the belly, and his insides spilled out on the ground. He died immediately, and Joab did not have to strike again. Then Joab and his brother Abishai went on after Sheba.