The sanctity of the soul remains even when the body is violated, the sanctity of the body is not lost; and that, in like manner, the sanctity of the body is lost when the sanctity of the soul is violated, though the body itself remains intact.
City of God, Book I, chapter 16.
Augustine's comments were made during a discussion of the virgin martyrs in the early church who chose martyrdom rather than be sexually violated.
He counsels that victims of sexual abuse should not feel shame since the blame for the sexual transgression is not their own, but rather on the aggressor.
The mind and will can remain pure and chaste, even in face of non voluntary acts the body is made to perform.