Ahimaaz son of Zadok again said to Joab, "Come what may, please let me run behind the Cushite." But Joab replied, "My son, why do you want to go? You don't have any news that will bring you a reward."
He said, "Come what may, I want to run." So Joab said, "Run!" Then Ahimaaz ran by way of the plain and outran the Cushite.
References for 2 Samuel 18:23