In Peace on Earth Joseph Grassi emphasizes the practical means Jesus suggests to make peace a reality. He focuses on the roots of peace and justice found in the non-violent and compassionate life and teachings of Jesus. Grassi teaches that Luke's summary of Jesus' teaching in the "Sermon on the Plain" has a central place as a practical guide for believers to develop a life of peace and non-violence in imitation of Jesus as a non-violent Messiah. Luke's Jesus goes to the roots of true peace through the practice of non-violent, Love, compassionate justice, true repentance, and forgiveness. External power and domination are renounced and replaced by inner power, humble service, and a priority for the needs of the poor and marginalized.