Zenkei Shibayama said this quote

“ Certainly human culture may have achieved great progress in the course of history. Suffering and unhappiness in the human world, however, do not seem to have decreased. The present situation of our world is so full of poverty, distrust, diseases, strife, that there seems to be no end. Hundreds and thousands of great men admired as saints and sages have appeared in the world in the past, and they have devoted their lives for the betterment of the world. Human suffering and unhappiness, however, do not seem to have decreased or ended. Over and over again they repeatedly, thanklessly endeavoured to fill up the well with snow. The true life of Zen is found here, when we all become true Great Fools and calmly and nonchalantly keep on doing our best, realizing well that our efforts will never be rewarded. ”