“That is a simple rule, and easy to remember. When I, a thoughtful and unblessed Presbyterian, examine the Koran, I know that beyond any question every Mohammedan is insane; not in all things, but in religious matters. When a thoughtful and unblessed Mohammedan examines the Westminster Catechism, he knows that beyond any question I am spiritually insane.”

Source: The Greek Way (1930), Ch. 1

1 Corinthians 2:14,15 http://www.watchtower.org/e/bible/1co/chapter_002.htm
First Epistle to the Corinthians

Source: Memory, Sorrow, and Thorn, Stone of Farewell (1990), Chapter 8, “On Sikkihoq’s Back” (p. 188).

Song lyrics, Lionheart (1978)

Lecture III: Of the more Important Divisions and Essential Parts of Knowledge
A Course of Popular Lectures (1829)
Context: I must intreat your patience — your gentle hearing. I am not going to question your opinions. I am not going to meddle with your belief. I am not going to dictate to you mine. All that I say is, examine; enquire. Look into the nature of things. Search out the ground of your opinions, the for and the against. Know why you believe, understand what you believe, and possess a reason for the faith that is in you…
But your spiritual teachers caution you against enquiry — tell you not to read certain books; not to listen to certain people; to beware of profane learning; to submit your reason, and to receive their doctrines for truths. Such advice renders them suspicious counsellors. By their own creed, you hold your reason from their God. Go! ask them why he gave it.

Source: The Wise Man's Fear

Source: The Naked Civil Servant (1968), Ch. 27