How is Sister Tabitha an important member of the village in the novel, The Forest of Hands and Teeth?

Sister Tabitha is the head of the Sisterhood. She closely controls the actions and behaviors of the people of the village, so as not to offend God and provoke Him. Sister Tabitha is at once strict and kind, and manages to get Mary to realize that there is love outside of herself, and that being selfish is not a good thing. Sister Tabitha's selflessness is on full display when she attempts to keep the Cathedral doors open for Mary, Harry, Jacob, and Argos but is ultimately cut down by Gabriella's Unconsecrated form and savagely killed.