That which does not kill us makes us stronger.

Examine the lives of the best and more fruitful men and peoples, and ask yourselves whether a tree, if it is to grow proudly into the sky, can do without bad weather and storms: whether unkindness and opposition from without, whether some sort of hatred, envy, obstinacy, mistrust, severity, greed and violence do not belong to the favouring circumstances without which a great increase even in virtue is hardly possible. The poison which destroys the weaker nature strengthens the stronger – and he does not call it poison, either.

That which does not kill me makes me stronger.

We often refuse to accept an idea merely because the tone of voice in which it has been expressed is unsympathetic to us.

It is not a lack of love, but a lack of friendship that makes unhappy marriages.

The aphorism in which I am the first master among Germans, are the forms of 'eternity'; my ambition is to say in ten sentences what everyone else says in a book - what everyone else does not say in a book.