(Clearwisdom.net)
Once, in ancient times, there was a couple who cultivated Buddhahood. They were very diligent and offered bundles of incense to the Buddha statue everyday, yet they had not achieved anything, even though they had practiced the majority of their lives. So they decided to go see the Buddha and ask why. They also brought with them a big load of ashes from the burnt incense. Along the way, the couple encountered two thieves. Since the couple had little money, they taught the thieves about Virtue and how to cultivate Buddhahood. The two thieves listened intently and decided to stop their dishonest activity and accompany the couple to see the Buddha.
When the four people met Buddha, they explained their reasons for visiting. Buddha gave them each an iron eggplant, and told them to cook the iron eggplants for 49 days. Once the eggplants were cooked, they could eat them and complete their cultivation to Buddhahood .
The four people journeyed back and divided the work among themselves. The two former thieves would go to the mountains everyday to collect the firewood, and the couple would stay home and cook the iron eggplants. Following the Buddha's instruction, 49 days later, the two former thieves' eggplants were well cooked, and after eating them, the two succeeded in cultivation and left. However the couple's eggplants were still not cooked.
The reason for the eggplants not being cooked was this: when the couple cooked the four eggplants, they always put their own eggplants in the best spot in the pot.