There is a simple test by which you can tell a true teacher from a false one.

It is this: If they point you to their own personality; if they make special claims for themselves; if they say that they have received any special privileges from God that are not equally accessible to the whole human race anywhere; if they attempt in their own name or in that of an organization to establish under any pretense a monopoly of the truth about God, then, however imposing their credentials, however pleasing their personality may be, they are a false teacher, and you had better have nothing to do with them.

If, on the contrary, they tell you to look away from themselves, to seek the Presence of God in your own heart, and to use books, lectures, and churches only as a means to that one end, then, however humble their efforts may be, however lacking their own demonstration may seem, they are nevertheless a true teacher and are giving you the Bread of Life.
Alter Your Life ~ Emmet Fox - 1933

There is one quality which pre-eminently distinguishes the man of Truth from the man of self, and that is humility. To be not only free from vanity, stubbornness and egotism, but to regard one's own opinions as of no value, this indeed is true humility.
THE WAY OF PEACE BY JAMES ALLEN (1907)