A man who lived on the northern frontier of China was skilled in interpreting events. One day, for no reason, his horse ran away to the nomads across the border. Everyone tried to console him, but his father said, “What makes you so sure this isn’t a blessing?” Some months later his horse returned, bringing a splendid nomad stallion. Everyone congratulated him, but his father said, “What makes you so sure this isn’t a disaster?” Their household was richer by a fine horse, which his son loved to ride. One day he fell and broke his hip. Everyone tried to console him, but his father said, “What makes you so sure this isn’t a blessing?”
A year later the nomads came in force across the border, and every able-bodied man took his bow and went into battle. The Chinese frontiersmen lost nine of every ten men. Only because the son was lame did the father and son survive to take care of each other. Truly, blessing turns to disaster, and disaster to blessing: the changes have no end, nor can the mystery be fathomed.
The Lost Horse,
As told by Ellen J. Langer, in” The Power of Mindful Learning,” Reading, Mass: Addison-Wesley, page 99-100. (1997).
More versions of this story here.