A blind practitioner was having a Zen talk with his teacher. Questions of teaching lineage were bothering the student. "How can we know for sure if these are the Buddha's words or something written by his students?" he asked.
The sun disappeared and dark night descended.
Before he went on his way his teacher gave him a lantern with a lit candle.
"What shall I do with it?" asked the blind student, "I can not use it."
"A lantern will help others." said the teacher and slid the door shut.
The night was deep and silent. The blind monk held the lantern high and felt his way with a walking stick. Suddenly, after walking for about an hour, the blind guy bumped into someone so forcefully that they both fell down.
"Can't you see where you're going?" asked the blind man angrily. "Your candle went out, my brother," said the other guy softly.