What does this quote mean Upon the plains of hesitation bleach bones countless millions who when on dawn victory paused to rest and there resting died?

This quote is a warning against letting hesitation and comfort stand in the way of achieving one's goals. The "plains of hesitation" are a metaphorical place where people allow their fear and doubt to cause them to become stagnant. The "bones countless millions" represent the countless people who have given up on their dreams and aspirations, or failed to take action when it was required, and as a result, never achieved their full potential. The quote serves as a reminder that time and opportunity wait for no one, and that those who hesitate and pause on their path towards victory are likely to meet with defeat and regret.