44 Again, this concern for the needs of the whole Church is a true mark of the Catholic character of the living Church. "Zeal for missionary activity and the Catholic spirit are one and the same. A principal note of the Church is catholicity; consequently, a man is no true member of the Church unless he is likewise a true member of the entire body of Christian believers and is filled with an ardent desire to see her take root and flourish in every land."
Source: Fidei Donum (Vatican.va)