How do we know a teacher?

How are we to know a teacher, then?
The sun requires no torch to make him visible;
we need not light a candle in order to see him.
When the sun rises,
we instinctively become aware of the fact,
and when a teacher of men
comes to help us,
the soul will instinctively know that Truth
has already begun to shine upon it.
Truth stands on its own evidence;
it does not require any other testimony
to prove it true;
it is self-effulgent.
It penetrates into the innermost corners of our nature,
and in its presence the whole universe stands up and says,
“This is Truth”.
The teachers whose Wisdom and Truth
shine like the light of the sun,
are the very greatest the world has known.