What do they do to the statue of Our Lady? Why?

"At Lily’s first meeting of the Daughters, August retells the story of Our Lady of Chains. The story involves a slave, Obadiah, finding a wooden figure of Mary. Obadiah retrieves the statue, and he hears the statue reassure him that she will take care of him. He brings the statue to the prayer house, and another slave named Pearl explains that the statue is the mother of Jesus. The people celebrate the statue and find strength from touching her heart. Soon, the master discovers the statue and chains it to a barn. Soon, however, the statue is found to have broken the chains.

After the story, the Daughters begin dancing, and then each of them slowly walks up to the statue of Mary to touch her heart. Lily is compelled to do the same, so she rises and walks toward Mary to touch her heart. As she does so, June stops playing the cello, and Lily realizes that she is not included in the ritual. August scolds June for her inhospitality, and Lily faints."