I agree that people should be in a mindset to be persistent, but I think “God helps those who help themselves” or “fortune favors the bold” may be more applicable. 
Pulling yourself up by your bootstraps is literally impossible, and that phrase used to mean that very thing. From Wikipedia (I know, I know):
In original use, often used to refer to pulling oneself over a fence, and implying that someone is attempting or has claimed some ludicrously far-fetched or impossible task.