Pope Pius XII said in Mystici Corporis: "If we would define this true Church of Jesus Christ - which is the One, Holy, Catholic, Apostolic Roman Church - we shall find nothing more noble, more sublime, or more divine than the expression 'the Mystical Body of Jesus Christ'- an expression which springs from and is, as it were, the fair flowering of the repeated teaching of the Sacred Scriptures and the Holy Fathers."
There is no such thing as a "partial communion" between the Roman Catholic Church and non-Catholic religions or sects . To assert that there is a partial communion between the Roman Catholic Church and non-Catholic sects is overtly heretical, since it is directly contrary to the Church's teaching.
Pope Pius IX: "None [of these religious societies differing among themselves and separated from the Catholic Church], not even taken as a whole, constitutes in any way and are not that one, Catholic Church founded and made by Our Lord and which He wished to create. Further, one cannot say in any way that these societies are either members or parts of that same Church, because they are visibly separated from Catholic Unity."
Pope Leo XIII: "Jesus Christ never conceived of nor instituted a Church formed of many communities which were brought together by certain general traits - but which would be distinct one from another and not bound together among themselves by ties which make the Church one and indivisible - since we clearly profess in the Creed of our Faith: " 'I believe in one...Church.' "
Pope Pius XI: "It is absurd and ridiculous to say that the Mystical Body can be formed out of separated and disjunct members."
Pope Pius XI: "It is to depart from divine truth to imagine a Church which one can neither see nor touch, which would be nothing more than spiritual in which numerous Christian communities would be united by an invisible bond, even though they are divided in faith
