2 Samuel 23:17-18

17“The Lord forbid that I should drink this!” he exclaimed. “This water is as precious as the blood of these men who risked their lives to bring it to me.” So David did not drink it. These are examples of the exploits of the Three.

18Abishai son of Zeruiah, the brother of Joab, was the leader of the Thirty. He once used his spear to kill 300 enemy warriors in a single battle. It was by such feats that he became as famous as the Three.