Isaiah 21:10

7 and when he seeth a troop, horsemen in pairs, a troop of asses, a troop of camels, he shall hearken diligently with much heed.

8 And he cried as a lion: O Lord, I stand continually upon the watch-tower in the day-time, and am set in my ward whole nights;

9 and, behold, here cometh a troop of men, horsemen in pairs. And he answered and said, Fallen, fallen is Babylon; and all the graven images of her gods are broken unto the ground.

10 O thou my threshing, and the grain of my floor! that which I have heard from Jehovah of hosts, the God of Israel, have I declared unto you.

11 The burden of Dumah. One calleth unto me out of Seir, Watchman, what of the night? Watchman, what of the night?

12 The watchman said, The morning cometh, and also the night: if ye will inquire, inquire ye: turn ye, come.

13 The burden upon Arabia. In the forest in Arabia shall ye lodge, O ye caravans of Dedanites.