“Most of us have jobs that are too small for our spirits.”

2009, First Inaugural Address (January 2009)
Context: What the cynics fail to understand is that the ground has shifted beneath them — that the stale political arguments that have consumed us for so long no longer apply. The question we ask today is not whether our government is too big or too small, but whether it works — whether it helps families find jobs at a decent wage, care they can afford, a retirement that is dignified. Where the answer is yes, we intend to move forward. Where the answer is no, programs will end.

Book 1, Chapter 3 “Peculiar Geography of an Unknown Realm” (p. 167)
The Elric Cycle, The Revenge of the Rose (1991)

Too Busy Not to Pray (2008, InterVarsity Press)

Alfred P. Sloan. quoted in: John Bourne (2000), Learning Effectiveness and Faculty Satisfaction. p. 11

Attributed without citation in Ken Robinson, The Element (2009), p. 260. Widely attributed to Michelangelo since the late 1990s, this adage has not been found before 1980 when it appeared without attribution in E. C. McKenzie, Mac's giant book of quips & quotes.
Disputed
Variant: The greatest danger for most of us is not that our aim is too high and we miss it, but that it is too low and we reach it.

Speech to the American Bar Association (2 September 1925).
Context: The most ominous spirit of our times, as it seems to me, is the indication of the growth of an intolerent spirit. It is the more dangerous when armed, as it usually is, with sincere conviction. It is a spirit whose wrath must be turned away by the soft answers of a sweet reasonableness. It can be exorcised only by invoking the Genius which watched over our infancy and has guided our development— a good Genius— still potent let us believe — the American spirit of civil and religious liberty. Our institutions were not devised to bring about uniformity of opinion; if they had we might well abandon hope. It is important to remember, as has well been said, "the essential characteristic of true liberty is that under its shelter many different types of life and character and opinion and belief can develop unmolested and unobstructed."

Iowa stump speech. http://www.rollingstone.com/nationalaffairs/index.php/2008/03/11/sinbad-on-his-and-hillarys-red-phone-moments-in-bosnia/
Presidential campaign (January 20, 2007 – 2008)

On the Mindless Menace of Violence (1968)
Context: Our lives on this planet are too short and the work to be done too great to let this spirit flourish any longer in our land. Of course we cannot vanquish it with a program, nor with a resolution. But we can perhaps remember, if only for a time, that those who live with us are our brothers, that they share with us the same short moment of life; that they seek, as do we, nothing but the chance to live out their lives in purpose and in happiness, winning what satisfaction and fulfillment they can. Surely, this bond of common faith, this bond of common goal, can begin to teach us something. Surely, we can learn, at least, to look at those around us as fellow men, and surely we can begin to work a little harder to bind up the wounds among us and to become in our own hearts brothers and countrymen once again.