St. Francis, in the acting out of his life, as the medieval historian Fredreich Heer pointed out decades ago, provided a prophetic challenge to a wide range of persons in his own time.
To the Cathars, Francis preached that the material world is good because it comes as creation as a first revelation of God’s very own self and second, because the world in which we live has been recreated (see the Prologue to John’s Gospel) in the Incarnation. There is a profound nexus between creation and Incarnation. This is the basic sacramental stance of Francis: everything is a sign of God’s presence in the world. It is in this basic sacramental foundation that we must understand Francis’s profound pietas toward the cre- ated world. Not to link that pietas to Francis’s faith in the goodness of creation runs the risk of reducing Francis to a sentimental icon (and this has been a problem since the nineteenth century). That reading of Francis has had some unfortunate results, as an early editor of Butler’s Lives of the Saints has observed somewhat impatiently: “religious and social cranks of all sorts have appealed to him for justification and he has completely won over the hearts of the sentimental.”
To the majores, Francis spoke of the dignity of the poor and the outcast. That he “borrowed” his father’s commercial goods to further his own aims of literally rebuilding a church and helping the lepers was the slightly subversive act of nay-saying in the face of an emergent capitalist mercantile class. That he stripped himself naked before that same father was his definitive rejection of the monied culture. The distaff side of that rejection was his identification with the poor: “While I was in sin,” he wrote in the Testament, “it seemed very bitter to me to see lepers. And the Lord Himself led me to them and I had mercy on them. And when I left them that which seemed bitter to me was changed into sweetness of soul and body.”
To the towns and cities of Italy, he preached peace and reconcil- iation to a civil society riven by vendettas and family war, just as he transformed his early aspirations to be a soldier to become an unarmed missionary crossing over Crusader lines (in the company of the aptly named Brother Pacifico) to speak to the caliph. He was a peacemaker at a time when there was little peace either in the towns of Umbria or at the edges of Christian society. His life illustrates the awful truth that makers of peace can only accomplish their desires when possessed of peace themselves.
Finally to the Church, he illustrated that everything flows from faith in the person of Jesus Christ. His allegiance to the Church derived not from loyalty to an institution but from the conviction that it was within the Church that he could best find and embrace Christ. His expressed desire that his friars be Catholic and avoid the heretical sects (explicit in his versions of the Rule) is to be found both in his understanding of the Church as the body of Christ and, further, I think, from his fundamental distaste for schism, chaos, and sectarianism at the civil level—dissensions he fought against throughout his public life.
Source: Cunningham, Lawrence Francis of Assisi as a Catholic Saint. Logos: A Journal of Catholic Thought and Culture, Volume 9, Number 1, Winter 2006, pp. 56-71