Live today!

The load of tomorrow, added to that of yesterday,
carried today, makes the strongest falter.

Salutation to the dawn

Look to this day!
For it is life, the very life of life.
In its brief course
Lie all the verities and realities of your existence:
The bliss of growth
The glory of action
The splendor of beauty,
For yesterday is but a dream
And tomorrow is only a vision,
But today well lived makes every yesterday
a dream of happiness
And every tomorrow a vision of hope.
Look well, therefore, to this day!
Such is the salutation to the dawn.

From Dale Carnagie's book How to Stop Worrying and Start Living