Source
A Joseph Campbell Companion: Reflections on the Art of Living
A posthumous collection of short sayings, published in 1991 from material gathered by Diane K. Osbon, who said she wrote them down in her journals over years in Campbell's company. Because the lines were recorded by a listener rather than written by Campbell, their exact wording rests on her notes.
Little is known for certain here; this background is thin and may be revised.
References
Quotes (1)
“The very cave you are afraid to enter turns out to be the source of what you are looking for.”
— Joseph Campbell, A Joseph Campbell Companion (1991), ed. Diane K. Osbon, 'In the Field', from her notes of his talk; checked in the Internet Archive scan of the HarperCollins 1991 edition. The popular form "The cave you fear to enter holds the treasure you seek" is not found in his works; Quote Investigator's earliest print instance is 2004Watch on YouTube: Jocko Willink's advice on facing challenges ↗Jocko Willink on moving toward the challenge (fan compilation)