The most immutable barrier in nature is between one man's thoughts and another's.
The greatest discovery of any generation is that a human being can alter his life by altering his attitude.
The first thing to learn in intercourse with others is non-interference with their own peculiar ways of being happy, provided those ways do not assume to interfere by violence with ours.
The art of being wise is the art of knowing what to overlook.
The aim of a college education is to teach you to know a good man when you see one.
Let everything you do be done as if it makes a difference.
No matter how full a reservoir of maxims one may possess, and no matter how good one's sentiments may be, if one has not taken advantage of every concrete opportunity to act, one's character may retain entirely unaffected for the better.
You cannot fly like an eagle with wings of a wren.
Most people live, whether physically, intellectually, or morally, in a very restricted circle of their being. They make use of a very small portion of their possible consciousness, and of their soul's resources in general, much like a man who, out of his whole bodily organism, should get into the habit of using and moving only his little finger. Great emergencies and crises show us how much greater our vital resources are than we had supposed.
Mankind's common instinct for reality has always held the world to be essentially a theatre for heroism. In heroism, we feel, life's supreme mystery is hidden. We tolerate no one who has no capacity whatever for it in any direction. On the other hand, no matter what a man's frailties otherwise may be, if he be willing to risk death, and still more if he suffer it heroically, in the service he has chosen, the fact consecrates him forever.