LITTLE FLOWERS OF SAINT FRANCIS OF ASSISI, Chapter 13
HOW ST FRANCIS AND BROTHER MASSEO PLACED THE BREAD THEY HAD BEGGED UPON A STONE NEAR A FOUNTAIN, AND HOW ST FRANCIS PRAISED THE VIRTUE OF HOLY POVERTY, PRAYING ST PETER AND ST PAUL TO MAKE HIM LOVE HOLY POVERTY GREATLY, AND HOW ST PETER AND ST PAUL APPEARED TO HIM
Poverty. Jesus turned our sense of values upside down with His beatitudes, mentioning various things we had previously thought to be misfortunes, and calling them blessings. He gave His reasons, and that's the sort of thing Brother Francis is talking about here.
It's interesting that miraculous occurences are just mentioned in passing. This story is about poverty being a treasure.