What is the theme in Petra: City in Stone by T. L. Higley?

The main conflict with which both Cassia and Julian struggle is their sense of independence. For Cassia, this struggle for independence comes from a long history of abandonment and abuse at the hands of the men who were supposed to love her. After leaving Aretas, Cassia swears that she will never again be controlled by a man - neither real nor spiritual. For this reason, she struggles to understand her relationships with Julian and his Savior, Jesus Christ.