“From of old, a thousand thoughts, in his pilgrimings and wanderings, had been in this man: What am I? What is this unfathomable Thing I live in, which men name Universe? What is Life; what is Death? What am I to believe? What am I to do? The grim rocks of Mount Hara, of Mount Sinai, the stern sandy solitudes answered not. The great Heaven rolling silent overhead, with its blue-glancing stars, answered not. There was no answer. The man's own soul, and what of God's inspiration dwelt there, had to answer!”

15
Golden Sayings of Epictetus

Source: The Hero and the Crown

Source: Cathedral

Section 54
The Passionate State Of Mind, and Other Aphorisms (1955)

Last words (27 July 1946) as told by Alice B. Toklas in What Is Remembered (1963)

As quoted in Writers on Writing‎ (1986) by Jon Winokur.
Variant: If you ask me what I came into this life to do, I will tell you: I came to live out loud.

Australians in a Nuclear War (1983)
Context: Many of those who hear me believe I am putting on an act, while others who had considered I am one who surely knows the answers, are depressed to find that, by my own admission, I don't. What I do know for certain is that what is regarded as success in a rational materialistic society only impresses superficial minds. It amounts to nothing and will not help us rout the destructive forces threatening us today. What may be our salvation is the discovery of the identity hidden deep in any one of us, and which may be found in even the most desperate individual, if he cares to search the spiritual womb which contains the embryo of what can be one's personal contribution to truth and life.

Source: Eat, Pray, Love

Source: Green Mars (1993), Chapter 8, “Social Engineering” (p. 401)