Right at the beginning is the beautiful and clear intuition of St. Francis that is the root of Franciscan sine proprio and holy poverty:
The poverty and austerity of Saint Francis were no mere veneer of asceticism, but something much more radical: a refusal to turn reality into an object simply to be used and controlled. (11)That is Franciscanism. It is the admission that nothing, not a thing or a place or a person or even your own self belongs to you alone. It is a confession that you yourself are not god, are not the center of the universe, and that other persons and things have ends and purposes and joys that are apart from your use or enjoyment of them.
In human relationships, this holy poverty is called chastity. Pope Francis is helping us to see that we need to find together a new chastity toward our sister mother earth.