While David was sitting between the inner and outer gates, the watchman1 went up to the roof of the gateway by the wall. As he looked out, he saw a man running alone.
References for 2 Samuel 18:24
The watchman called out to the king and reported it. The king said, "If he is alone, he must have good news." And the man came closer and closer.
Then the watchman saw another man running, and he called down to the gatekeeper, "Look, another man running alone!" The king said, "He must be bringing good news,2 too."
References for 2 Samuel 18:26
The watchman said, "It seems to me that the first one runs like3 Ahimaaz son of Zadok." "He's a good man," the king said. "He comes with good news."
References for 2 Samuel 18:27