Chapter 40 begins the portion of this book that Bible scholars call 2nd Isaiah. The original audience for this material was living in the time of the Babylonian exile.
We can imagine their plight. Many of us can remember our own plights--times of feeling lost or uncared for. The prophet reminds us that we are not solely at the mercy of whatever, whoever, stands for Babylon in our lives: Have you not known? Have you not heard? Come on, haven't you always known who always was in charge?
In their time, they were to be rescued from exile by the Persia army led by Cyrus. God saved them from unbelievers through the efforts of unbelievers. Nothing that unusual here. After all, Pharaoh let them leave their unpleasant jobs at pyramid building.
Babylon that seems so powerful to everyone who was alive did not seem like that big a deal to God. "Scarcely are they planted, scarcely has their stem taken root in the earth, when he blows upon them, and they wither, and the tempest carries them like stubble."