Lamp of a Buddha

King Ajatasatru invited the Buddha to preach and offered as a token of his piety several tens of thousands of lamps. At the time, an old woman (named Nanda) who had been begging, and had only managed to collect two coins, bought some oil with them and offered it all in a small lamp to the Buddha. [With this offering she vowed to eliminate the darkness of the sufferings of all people.] Old and hungry, she later collapsed and died.

By the next morning the many lamps offered by the king had already burned themselves out, but the lamp of the poor old woman was still burning with increasing brilliance. When it proved impossible to extinguish it, the Buddha explained that it was so because of the donor's extremely fervent faith and transcendental vow. 'The light of a Buddha can never be extinguished' said the Buddha who then predicted that she would attain Buddhahood."

~ Thus Have I Heard, Translated by the Sutra Translation Committee