WHO ARE WE?

Am I not today my yesterday,
Always the master of my past,
That I may seek to cast away,
But while I live will always last.
All that I am is yesterday;
All change takes plays in yore.
Those things that have long gone away
That could not exist before.
Who were we before we were born,
Before we had a past?
Who will we be when comes the dawn
And we see our shadow cast?
The end of time when we forlorn
Find we are but the past.