What is the lesson behind the story of the woman who wanted to fast in Chapter 32?

The story of the woman in Chapter 32 serves to illustrate a profound spiritual lesson. She arrived with a firm intention to fast for three days, but her plan was altered. As the chapter explains, she was made to prepare puranpolis and then eat them to her heart's content. The underlying teaching, as stated in Chapter 32, is that "wearing out the body for others' sake - this blessed act is true welfare." This experience was designed to make her understand, in a way she would never forget, that selfless service can be a higher virtue than personal austerity like fasting.