“He who is not courageous enough to take risks will accomplish nothing in life.”
This quote has no known author and is recorded as an anonymous proverb.
About this quote
It reads like a boxer talking about the difference between a career and a cautious job, and Ali is a plausible source given how often the sentence appears in sports writing. Whatever its origin, it states the plain bargain of risk: the reward is on the far side of the thing you are afraid of.