Answer: It's about achieving your goals, no matter the situation.
Explanation:
You know the meaning of the word "exodus" ? Well, basically it's the march that a population perform from one place to another, looking for better opportunities or even a different life style.
This metaphor talks about how anyone can cross through rivers, mountains and valleys in order to achieve an specific goal.
A clear example? Self-improvement.
Not even the overwhelming heat of a "desert" can stop human will.