2 Samuel 18:24-27
And David sat between the two gates: and the watchman went up to the roof over the gate to the wall, and lifted up his eyes, and looked, and behold a man running alone.
Torrey's Topical Textbook—AKJV

2 Kings 9:18-20
So there went one on horseback to meet him, and said, Thus said the king, Is it peace? And Jehu said, What have you to do with peace? turn you behind me. And the watchman told, saying, The messenger came to them, but he comes not again.
Torrey's Topical Textbook—AKJV

Isaiah 21:6,7,9
For thus has the LORD said to me, Go, set a watchman, let him declare what he sees.
Torrey's Topical Textbook—AKJV