Once upon a time an old couple and a young couple lived contentedly together as a single extended family. The old couple did all of the work in order to remain useful in this life and to prevent the young people from thinking them useless. As a result, the young couple never learned to do anything for themselves.
Eventually the old couple died. The young couple ate all of the food stored in the house, but did not know how to produce more, so they sold the house to buy food and they moved into a straw shack. When winter arrived, they were cold and hungry and entirely miserable in their shack, where they lived entirely on rice gruel made from water and the few grains they were able to retrieve from the straw in the shack.
One day, on the 8th day of the 12th lunar month, a gust of wind came up and blew down the shed, crushing them to death.
Ever since that time, on the 8th day of the 12th lunar month, the festival of Làbā 腊八, people have made a congee (porridge) of different grains to remind them of the necessity of knowing how to work.