Charles Ellicott Commentary 2 Samuel 18:22

"Then said Ahimaaz the son of Zadok yet again to Joab, But come what may, let me, I pray thee, also run after the Cushite. And Joab said, Wherefore wilt thou run, my son, seeing that thou wilt have no reward for the tidings?" — 2 Samuel 18:22 (ASV)

No tidings ready. —The phrase is a difficult one, and is translated by the Septuagint “no tidings leading to profit,” and by the Vulgate “thou wilt not be a bearer of good tidings.” The simplest and most probable sense is “no tidings sufficient” for a special messenger; the Cushite had already carried the news.