When is tomorrow?  
When tomorrow comes it will no longer be tomorrow
When tomorrow comes it will be today

What is later?
When later comes it will no longer be later
When later comes it will be now

But you can't say I'll do it today and then do it tomorrow
That would be a lie

You can't say I'll do it now and then do it later
Then you would be cheating yourself.

Or are you

Because if tomorrow becomes today
And if you say you'll do it today
But you do it tomorrow
Then you held true to your promise

Because if later becomes now
And if you say you'll do it now
But you do it later
Then no one can say you're wrong