The following is a letter written by Abraham Lincoln to the Headmaster of a school in
which his son was studying. It contains advice, which is still relevant today for executives, workers, teachers, parents and students.

A WORD TO TEACHERS

He will have to learn, I know, that all men are not just and are not
true. But teach him if you can the wonder of books… but also give
him quiet time to ponder the eternal mystery of birds in the sky,
bees in the sun and flowers on a green hillside.
In school, teach him it is far more honorable to fall than to cheat. 
Teach him to have faith in his own ideas, even if everyone tells him he is
wrong.
Teach him to be gentle with gentle people and tough with the tough.
Try to give my son the strength not to follow the crowd when
everyone is getting on the bandwagon.
Teach him to listen to all men; but teach him also to filter all he
hears on a screen of truth, and take only the good that comes
through.
Teach him, if you can, how to laugh when he is sad… Teach him
there is no shame in tears.
Teach him to scoff at cynics and to be aware of too much sweetness.
Teach him to sell his brawn and brain to highest bidders, but never
to put a price on his heart and soul. Teach him to close his ears to a
howling mob… and stand and fight if thinks he is right.
Treat him gently, but do not cuddle him, because only the test of fire
makes fine steel. Let him have the courage to be impatient. Let him
have the patience to be brave. Teach him always to have sublime
faith in himself, because then he will have faith in humankind.
This is a big order, but see what you can do. He is such a fine little
fellow my son!
- Abraham Lincoln