When a Bodhisattva teaches and spreads the Dharma it is sometimes called an Inexhaustible Lamp.
This is because it can bring thousands to the mind that is set on Supreme Enlightenment. If a Bodhisattva’s wish to guide others on the path is strong, then it will be Inexhaustible.
Thanks to the Bodhisattva’s Inexhaustible Lamp others will be motivated and inspired. Like a candle, the teachings do not decrease by being shared. That’s why they are called Inexhaustible.