Never put off until tomorrow,
what you can do today.
For when it comes tomorrow,
you will have forgotten
what it was you wanted to say.
Never leave it until tomorrow
or your chance would have gone away.
By leaving it until tomorrow
something could be out of your grasp,
The chance you had for happiness
might have up and flown away.
So never, put off until tomorrow,
what you can do today.

David Harris

http://www.poemhunter.com/poem/never-put-off-until-tomorrow/