'Watchman' in the Bible

For thus said the Lord unto me: 'Go, station the watchman, That which he seeth let him declare.'

The burden of Dumah. Unto me is one calling from Seir 'Watchman, what of the night? Watchman, what of the night?'

The watchman hath said, 'Come hath morning, and also night, If ye inquire, inquire ye, turn back, come.'