“We start with enthusiasm — out we go each of us to our task in all the brightness of sunrise, and hope beats along our pulses; we believe the world has no blanks except to cowards, and we find, at last, that, as far as we ourselves are concerned, it has no prizes; we sicken over the endless unprofitableness of labour most when we have most succeeded, and when the time comes for us to lay down our tools we cast them from us with the bitter aching sense, that it were better for us if it had been all a dream. We seem to know either too much or too little of ourselves — too much, for we feel that we are better than we can accomplish; too little, for, if we have done any good at all, it has heen as we were servants of a system too vast for us to comprehend. We get along through life happily between clouds and sunshine, forgetting ourselves in our employments or our amusements, and so long as we can lose our consciousness in activity we can struggle on to the end. But when the end comes, when the life is lived and done, and stands there face to face with us; or if the heart is weak, and the spell breaks too soon, as if the strange master-worker has no longer any work to offer us, and turns us off to idleness and to ourselves; in the silence then our hearts lift up their voices, and cry out they can find no rest here, no home. Neither pleasure, nor rank, nor money, nor success in life, as it is called, have satisfied, or can satisfy; and either earth has nothing at all which answers to our cravings, or else it is something different from all these, which we have missed finding — this peace which passes understanding — and from which in the heyday of hope we had turned away, as lacking the meretricious charm which then seemed most alluring.
I am not sermonizing of Religion, or of God, or of Heaven, at least not directly.”

Source: American Gods (2001), Ch. 6

Source: Sailing the Wine-Dark Sea: Why the Greeks Matter (2003), Ch.VII The Way They Went: Greco-Roman Meets Judeo-Christian

Author's Remarks.
Under the Banner of Heaven: A Story of Violent Faith (2003)
Context: I don't know what God is, or what God had in mind when the universe was set in motion. In fact, I don't know if God even exists, although I confess that I sometimes find myself praying in times of great fear, or despair, or astonishment at a display of unexpected beauty. There are some ten thousand religious sects — each with its own cosmology, each with its own answer for the meaning of life and death. Most assert that the other 9,999 not only have it completely wrong but are instruments of evil, besides. None of the ten thousand has yet persuaded me to make the requisite leap of faith. In the absence of conviction, I've come to terms with the fact that uncertainty is an inescapable corollary of life. An abundance of mystery is simply part of the bargain — which doesn't strike me as something to lament. Accepting the essential inscrutability of existence, in any case, is surely preferable to its opposite: capitulating to the tyranny of intransigent belief. And if I remain in the dark about our purpose here, and the meaning of eternity, I have nevertheless arrived at an understanding of a few modest truths: Most of us fear death. Most of us yearn to comprehend how we got here, and why — which is to say, most of us ache to know the love of our creator. And we will no doubt feel that ache, most of us, for as long as we happen to be alive.

page 332
A Million Little Pieces (2003)

Letter VI
The Nemesis of Faith (1849)

2010s, Farewell Speech (2017)
Context: When you encounter obstacles — because I guarantee you, you will, and many of you already have — when you are struggling and you start thinking about giving up, I want you to remember something that my husband and I have talked about since we first started this journey nearly a decade ago, something that has carried us through every moment in this White House and every moment of our lives, and that is the power of hope — the belief that something better is always possible if you're willing to work for it and fight for it.
It is our fundamental belief in the power of hope that has allowed us to rise above the voices of doubt and division, of anger and fear that we have faced in our own lives and in the life of this country. Our hope that if we work hard enough and believe in ourselves, then we can be whatever we dream, regardless of the limitations that others may place on us. The hope that when people see us for who we truly are, maybe, just maybe they, too, will be inspired to rise to their best possible selves.

2013, Cape Town University Address (June 2013)
Context: We always have the opportunity to choose our better history. We can always understand that most important decision -- the decision we make when we find our common humanity in one another. That’s always available to us, that choice. [... ] it can be heard in the confident voices of young people like you. It is that spirit, that innate longing for justice and equality, for freedom and solidarity -- that’s the spirit that can light the way forward. It's in you.

Chap. 8 : Change Your Circumstances by Changing Your Attitude
The Laws of Human Nature (2018)