The quote "God be merciful to me a sinner" from Luke 18:13 reflects a plea for forgiveness and humility, highlighting the idea that true repentance requires acknowledgment of one’s flaws. In the context of Martina Cole's novel "Revenge," this theme resonates throughout the characters' journeys, illustrating their struggles with guilt, loss, and the desire for redemption. The pursuit of vengeance often leads to moral dilemmas, forcing characters to confront their inner demons.