No Illusion Greater Than Fear
From Loa Tzu's statement in the Tao Te Ching...
“There is no greater illusion than fear, no greater wrong than preparing to defend yourself, no greater misfortune than having an enemy. Whoever can see through all fear will always be safe."
...I can only conclude that he was aware that we are creating our reality with our very own thoughts and beliefs and that by dwelling on, or worse yet, acting on our fears we only increase the chances of manifesting those fears. Hence conversely, whoever can dispel all their fears will always be safe.