King Zhuang of Chu threw a banquet for a bunch of his ministers. As nightfall approached, many of them became tipsy. At one point, the candles blew out, and someone took advantage of the darkness to grab at the queen's garments. The queen caught hold of the cord which held the person's headpiece in place, yanked it off, then said to the king, "After the candles blew out, someone grabbed at my clothes. I yanked off the cord which holds his headpiece in place. Bring over a candle so that I can see who is missing a cord for their headpiece." The king said, "I have offered wine to these men, causing them to get tipsy and forget their manners. How can I, in good conscience, humiliate one of these gentlemen, just so that I can demonstrate the virtue of my wife?" With that, he instructed his attendents, saying, "For all of those who are now drinking with me, anyone who doesn't remove the cord holding their headpiece will bring me displeasure." After more than 100 ministers removed the cords which held their headpieces in place, all of the candles were relit. All of the king's subjects were happy, and that was the end of it. Three years later, Jin made war with Chu. One of the king's ministers was constantly in the front ranks. He fought in five bouts, defeating the enemy, and causing them to retreat in each case. King Zhuang thought it strange, and asked him, "I am not a particularly virtuous person, nor have I granted you any special favors. Why would you fight like this, as if your life depended on it?" The man responded, "I should have been put to death. A few years ago, I got drunk and forgot my manners. Your Majesty showed restraint and did not put me to death. I would never dare not overtly repay Your Majesty's covert kindness. I would rather put my life on the line and drown the enemy in my own blood, for I am the one whose headpiece cord was yanked off on that night." The Jin army was subsequently defeated, and Chu became stronger. This goes to show that covert kindnesses have overt rewards. (Wiktionary translation)