Sorrow
To Sorrow I bade good-morrow,And thought to leave her far away behind;
But cheerly, cheerly, She loves me dearly:
She is so constant to me, and so kind.
— Keats, Endymion
Sorrow helps us immensely. It is apt to humble our pride. It chastens us. It opens our hearts to magnanimity and sympathy. To check our innumerable errors and make us watch ourselves and put us on the road to perfection, sorrow must necessarily exist in the world.
How beautiful and penetrating are the following lines of Tagore:
"Mother, I shall weave a chain of pearls for thy neck with my tears of sorrow.
  The stars have wrought their anklets of light to deck thy feet, but mine will hang upon thy breast.
  Wealth and fame come from thee and it is for thee to give or to withhold them. But this my sorrow is absolutely mine own, and when I bring it to thee as my offering thou rewardest me with thy grace.
  Gitanjali"
  The stars have wrought their anklets of light to deck thy feet, but mine will hang upon thy breast.
  Wealth and fame come from thee and it is for thee to give or to withhold them. But this my sorrow is absolutely mine own, and when I bring it to thee as my offering thou rewardest me with thy grace.
  Gitanjali"
Sri Chinmoy, Rabindranath Tagore: the moon of Bengal’s Heart, Agni Press, 2011