The Golden Rules of Conduct - William Shakespeare

Give thy thoughts no tongue,

Nor any unproportion'd thought his act.

Be thou familiar, but by no means vulgar.

Those friends thou hast, and their adoption tries,

Grapple them to thy soul with hopes of steel;

But do not dull thy palm with entertainment

Of each new-hatched, unfledged comrade. Beware

Of entrance to a quarrel, but being in,

Bear't that the opposed may beware of thee,

Give every man thy ear, but few thy voice:

Take each man's censure, but reserve thy judgment.

Costly thy habit as thy purse can buy,

But not express'd in fancy; rich, not gaudy;

For the apparel oft proclaims the man,

And they in France of the best rank and station

Are most select and generous thief in that.

Neither a borrower nor a lender be;

For loan oft loses both itself and friend,

And borrowing dulls the edge of husbandry.

This above all: to thine own self be true.

And it must follow, as the night the day,

Thou canst not then be false to any man.

- This monologue is taken from Hamlet. In my opinion it could almost be the original version of 'If' by Kipling. It carries strong messages about the ways in which one should live life. I love "This above all: to thine own self be true" - I believe as long as you are true to yourself you can't go wrong or be false to anyone else.