Certain good men appeal to me who are distinguished by enormous vehemence and zeal, and a conspicuous absence of brains; brethren who would talk for ever and ever upon nothing–who would stamp and thump the Bible, and get nothing out of it all; earnest, awfully earnest, mountains in labour of the most painful kind; but nothing comes of it all, not even the ridiculous mus. There are zealous abroad who are not capable of conceiving or uttering five consecutive thoughts, whose capacity is most narrow and their conceit most broad, and these can hammer, and bawl, and rave, and tear, and rage, but the noise all arises from the hollowness of the drum. I conceive these brethren will do quite well without education as with it, and therefore I have usually declined their applications.
-from Lectures To My Students