'Watchman' in the Bible

For so has the Lord said to me, Go, let a watchman be placed; let him give word of what he sees:

And the watchman gave a loud cry, O my lord, I am on the watchtower all day, and am placed in my watch every night:

The word about Edom. A voice comes to me from Seir, Watchman, how far gone is the night? how far gone is the night?

The watchman says, The morning has come, but night is still to come: if you have questions to put, put them, and come back again.