He who does a kindness to an ungrateful person, sets his seal to a flint and sows his seed upon the sand; on the former he makes no impression, and from the latter finds no product.

Defeat should never be a source of discouragement but rather a fresh stimulus.

The seven wise men of Greece, so famous for their wisdom all the world over, acquired all that fame, each of them, by a single sentence consisting of two or three words.

Similes prove nothing, but yet greatly lighten and relieve the tedium of argument.

An Aristotle was but the rubbish of an Adam, and Athens but the rudiments of Paradise.

Guilt upon the conscience, like rust upon iron, both defiles and consumes it, gnawing and creeping into it, as that does which at last eats out the very heart and substance of the metal.

Innocence is like polished armor; it adorns and defends.

Much reading is like much eating -wholly useless without digestion.

The covetous person lives as if the world were made altogether for him, and not he for the world.

Abstinence is the great strengthener and clearer of reason.

Most of the appearance of mirth in the world is not mirth, it is art. The wounded spirit is not seen, but walks under a disguise.

What you wish to be, be.

In fact, most of us see perseverance as a distinctly uncreative approach, the sort of strategy that people with mediocre ideas are forced to rely on.

When she told me her age I believed her - why not? she hasn't changed her story for five years.

The same way people are now paying a couple thousand dollars to fly to other parts of the world, people will be paying $50,000 to spend a weekend on a space station.

The wrong kind of praise creates self-defeating behavior. The right kind motivates students to learn.

Believe it can be done. When you really believe something can be done, your mind will find the ways to do it.

You think that when you love somebody you have to totally follow him or her. No, that's not love. When you love somebody, you have to be totally truthful with that person.

Confession is like a bridle that keeps the soul which reflects on it from committing sin, but anything left unconfessed we continue to do without fear as if in the dark.

I would always love to be an athlete, but it's got to be a tough day when you have to hang up those cleats.

The brave and capable women who served in Iraq and Afghanistan have performed admirably.