From a tale in the Huai Nan Zi.
It can be difficult to foresee the twists and turns through which fortune brings ruin and ruin brings fortune. There once was a man, skilled in divination, who lived close to the Northern frontier with his son. One day for no reason, the son’s horse ran away to the nomads across the border. Everyone tried to console him, but the father said, “What makes you so sure this isn’t a blessing?” Some months later the son’s 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 the 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 father and son survive to take care of each other. Truly, blessing turns to disaster, and disaster to blessing. This goes on without end, and the mystery can hardly be fathomed.