38 It is, therefore, not by chance that We are addressing Ourselves to you, Venerable Brethren, in this solemn hour of decision with regard to the spread of the Church. "Just as in our mortal frame, all the members suffer in union with each member, and the healthy members come to the aid of the ailing ones, so in the Church the individual members do not live for themselves alone but also assist the others and all render mutual aid to all, not only in comforting one another but also in contributing to the greater edification of the entire Body." To go further, must not the bishops "be considered the chief members of the universal Church, inasmuch as they are united by a peculiar bond to the Divine Head of the whole Body and are therefore properly called the principal parts of the Lord's body"?
Source: Fidei Donum (Vatican.va)