A nice little blog post from Dyneslines explains a common misquotation from Nietszche bandied around a lot nowadays:

As it often the case, the precept becomes more understandable when we turn to the original text, which reads: “Aus der Kriegsschule des Lebens - Was mich nicht umbringt, macht mich härter.” This observation stems from The Twilight of the Gods (Götzendämmerung) of 1888. It appears as number eight in a series of aphorisms that stand at the beginning of the book, so that it is not possible to deduce much context.

Still, the precept should be faithfully rendered. Yet the common English-language version incorporates a subtle, but serious error, for the last word is not “stronger” but “harder.” Thus what Nietzsche seems to be saying is that, even after contracting a terrible disease (AIDS for example), or being crippled in a car accident, we still need not despair. We can rise to the occasion by becoming “harder.” This does not mean that we are “stronger,” just more firmly resolved to deal with our lot.

Dullards know not goodness

Ay, let them laugh and revel o'er his fall! Perchance, albeit in life the missed him not, Dead, they will cry for him in straits of war. For dullards know not goodness in their hand, Nor prize the jewel till 'tis cast away. -- Sophocles, "Aias"