As “If you believed in me" dissolves, the hymn Rock of Ages begins at graveside.
let me hide myself in thee
let the water and the blood,
from thy wounded side which flowed,
be of sin the double cure;
save from wrath and make me pure.
"We'll get the child some water."
save from wrath and make me pure.
Addie was born “of sin”, from her mother's, “cleft", a “wound”; she was born in blood when her mother’s water broke.
Screenplay:
"Would you like some water, Addie?""We'll get the child some water."
Water and blood is a "double cure" of Addie's "sin" and makes her “pure”. Addie hid in her mother's cleft until born. "Let me hide myself in thee". Essie Mae, her mother, died in blood. Addie needs someplace to hide now that her mother is gone. She is a child, alone. She needs belief. She needs a savior. Belief in a savior. Addie has to cling to belief in something and in some being. She clings to Moze as her savior, believing him to be of the same "blood".
