In this sermon based on Matthew 18:21-35, Dr. Mark Rutland addresses the profound theme of forgiveness. Central to the message is the parable of the unmerciful servant, which Jesus uses to illustrate the boundless and merciful nature of divine forgiveness compared to human pettiness and vengefulness. The sermon explores the challenges of forgiving and receiving forgiveness, emphasizing the transformative power of grace in overcoming deep-seated resentments and personal failings.