Hildegard's sisters recorded and preserved her informal preaching in this collection of homilies on twenty-seven gospel pericopes. As teacher and superior to her sisters, Hildegard probably spoke to them in the chapter house, with the scriptural text either before her or recited from memory, according to Benedictine liturgical practice. Among her topics here are the themes of salvation history, the drama of the individual soul, the struggle of virtues against vices, and the life-giving and animating force of greenness (uiriditas).