… everyone who follows Christ receives true peace, the peace that Christ alone can give, a peace which the world cannot give. Many people, when they think of Saint Francis, think of peace; very few people however go deeper. What is the peace which Francis received, experienced and lived, and which he passes on to us? It is the peace of Christ, which is born of the greatest love of all, the love of the cross. It is the peace which the Risen Jesus gave to his disciples when he stood in their midst and said: “Peace be with you!”, and in saying this, he showed them his wounded hands and his pierced side (cf. Jn 20:19-20).
Franciscan peace is not something saccharine. Hardly! That is not the real Saint Francis! Nor is it a kind of pantheistic harmony with forces of the cosmos… That is not Franciscan either; it is a notion some people have invented! The peace of Saint Francis is the peace of Christ, and it is found by those who “take up” their “yoke”, namely, Christ’s commandment: Love one another as I have loved you (cf. Jn 13:34; 15:12). This yoke cannot be borne with arrogance, presumption or pride, but only with meekness and humbleness of heart.
… “Praised may you be, Most High, All-powerful God, good Lord… by all your creatures (FF, 1820). This is the beginning of Saint Francis’s Canticle. Love for all creation, for its harmony. Saint Francis of Assisi bears witness to the need to respect all that God has created, and that men and women are called to safeguard and protect, but above all he bears witness to respect and love for every human being. God created the world to be a place where harmony and peace can flourish. Harmony and peace! Francis was a man of harmony and peace. From this City of Peace, I repeat with all the strength and the meekness of love: Let us respect creation, let us not be instruments of destruction! Let us respect each human being. May there be an end to armed conflicts which cover the earth with blood; may the clash of arms be silenced; and everywhere may hatred yield to love, injury to pardon, and discord to unity. Let us listen to the cry of all those who are weeping, who are suffering and who are dying because of violence, terrorism or war, in the Holy Land, so dear to Saint Francis, in Syria, throughout the Middle East and everywhere in the world.
Text from http://en.radiovaticana.va/news/2013/10/04/popes_homily_for_solemn_mass_in_assisi/en1-734152 of the Vatican Radio website