'Watchman' in the Bible

Now the watchman was standing on the tower in Jezreel, and he spied the company of Jehu as he came, and said, "I see a company." Joram said, "Take a horseman, and send to meet them, and let him say, 'Is it peace?'"

So there went one on horseback to meet him, and said, "Thus says the king, 'Is it peace?'" Jehu said, "What do you have to do with peace? Fall in behind me!" The watchman said, "The messenger came to them, but he isn't coming back."

The watchman said, "He came to them, and isn't coming back. The driving is like the driving of Jehu the son of Nimshi; for he drives furiously."