If -

If you can keep your head when all about you
Are losing theirs and blaming it on you;
If you can trust yourself when all men doubt you,
But make allowance for their doubting too:
If you can wait and not be tired by waiting,
Or, being lied about, don't deal in lies,
Or being hated don't give way to hating,
And yet don't look too good, nor talk too wise;

If you can dream---and not make dreams your master;
If you can think---and not make thoughts your aim,
If you can meet with Triumph and Disaster
And treat those two impostors just the same:.
If you can bear to hear the truth you've spoken
Twisted by knaves to make a trap for fools,
Or watch the things you gave your life to, broken,
And stoop and build'em up with worn-out tools;

If you can force your heart and nerve and sinew
To serve your turn long after they are gone,
And so hold on when there is nothing in you
Except the Will which says to them: "Hold on!"

-Rudyard Kipling

If I could keep a cool head, if I trusted myself, if I were patient; if I could dream and not be beholden to my dreams, if I could conquer myself in victory and defeat, if I could let go of everything but my will to hold my heart and nerve. Would that there be a man left?