'Watchman' in the Bible

In the meantime Absalom fled. When the servant who was the watchman looked up, he saw many people coming from the west on a road beside the hill.

Now David was sitting between the inner and outer gates, and the watchman went up to the roof over the gate at the wall. When he looked, he saw a man running by himself.

So the watchman called out and informed the king. The king said, "If he is by himself, he brings good news." The runner came ever closer.

Then the watchman saw another man running. The watchman called out to the gatekeeper, "There is another man running by himself." The king said, "This one also is bringing good news."

The watchman said, "It appears to me that the first runner is Ahimaaz son of Zadok." The king said, "He is a good man, and he comes with good news."