A Shadow

I said unto myself, if I were dead,
  What would befall these children?  What would be
  Their fate, who now are looking up to me
  For help and furtherance?  Their lives, I said,
Would be a volume wherein I have read
  But the first chapters, and no longer see
  To read the rest of their dear history,
  So full of beauty and so full of dread.
Be comforted; the world is very old,
  And generations pass, as they have passed,
  A troop of shadows moving with the sun;
Thousands of times has the old tale been told;
  The world belongs to those who come the last,
  They will find hope and strength as we have done.