WITH GOD'S GRACE-
Look back and help for humanity's sake.
Measure your charity by the acts of others toward you
while you were climbing.
Forget not the past with all its good and ill reports.
Contemplate your future by the experiences you have had,
If you must strike to live, strike hard and sure.

Marcus Mosiah Garvey

http://www.poemhunter.com/poem/your-duty-to-morrow/