When a candle is lit in a dark room, it illuminates the room to some extent, but its power is limited. But if you use the same candle to light another candle, the total brightness increases. If you continue to do this, you can fill the room with brilliant illumination. The idea of transferring merit to others is like this. If we keep our own light selfishly hidden, it will only provide a limited amount of illumination. But when we share our light with others, we do not diminish our own light. Rather, we increase the amount of light available to all. Therefore, when others light our candle, we issue forth light. When out of gratitude we use our candle to light other people’s candles, the whole room gets brighter. This is why we transfer merit to others. This kind of light is continuous and inexhaustible.
Master Sheng Yen, “Rich Generosity”