Source: The Teachings of Don Juan: A Yaqui Way of Knowledge
“Sometimes, one must travel the most difficult path alone; only then can they endure the more challenging journeys in the future.”
1972
Related quotes

“Sometimes the darkest challenges, the most difficult lessons, hold the greates gems of light.”
Source: Family of Light: Pleiadian Tales and Lessons in Living

“The path shown by Jesus is a difficult one that can only be trod by true martyrs.”
Turning the Other Cheek to Terrorism (April 2008) http://archive.org/details/TurningTheOtherCheekToTerrorism
Context: The path shown by Jesus is a difficult one that can only be trod by true martyrs. A "martyr," etymologically, is he who makes himself a witness to his faith. And it is the ultimate testimony to one’s faith to be ready to put it to practice even when one’s very life is threatened. But the life to be sacrificed, it should be noted, is not the enemy’s life, but the martyr’s own life — killing others is not a testimony of love, but of anger, fear, or hatred. For Tolstoy, therefore, a true martyr to Jesus’ message would neither punish nor resist (or at least not use violence to resist), but would strive to act from love, however hard, whatever the likelihood of being crucified. He would patiently learn to forgive and turn the other cheek, even at the risk of death. Such would be the only way to eventually win the hearts and minds of the other camp and open up the possibilities for reconciliation in the "war on terror."

Source: "Energy: basic facts for an informed debate" https://www.youtube.com/watch?v=lRAMA4mT0z0, 2012.

Source: Approval Addiction: Overcoming Your Need to Please Everyone