Keen insight can come from an amateur. Keep your eye out for it. Sometimes the celebrity is mediocre.
Let not the authority of the writer offend thee, whether he be of great or small learning; but let the love of pure truth draw thee to read. Search not who spoke this or that, but mark what is spoken.
Men pass away, but the truth of the Lord remaineth for ever. God speaks unto us in different ways, without respect of persons.
-Thomas a Kempis, The Imitation of Christ, Book I, Ch. 5