The fact is that there is One Faith, One Body of Christ, One Gospel, and One Baptism. All others residing outside this REALITY are weighted down by the snares of false teachings. All such false teachings are identified by the Holy Body of Christ as anti-theological and all those who follow them are under the Holy Anathemas pronounced, each in turn, by the decisions of the Seven Ecumenical Councils.
A heresy of big proportions is the Ecumenist movement, fueled by a desire to unite all the disparate "fractions" of "christian denominationalism" under one universal umbrella without each such of them coming to terms with the myriads of doctrinal differences, (heresies), and especially without regard to following the Holy Canons of the Holy Body of Christ as set forth by the Seven Ecumenical Councils, the latter of which is of the utmost importance. The Ecumenists' goal seems determined to make a unique world religion which employs syncretistic practices in its ranks.
Do the Ecumenists really think that our Lord Jesus Christ had established a Holy Ecclesia that fails to be One and Unique? By doing so, do they not reveal a contemptable disbelief in that section of the Nicene Creed that states the Ecclesia is One? Therefore, dear brethren, make not the mistake of yearning for a property of the Ecclesia that it already possesses, and will always possess. Our job is to dispell heresy everywhere; completely and surely, without fail. We do this by teaching the Word of God, illumining all those in darkness with the Light of the Gospel. We then make disciples of those whom we teach, and baptize them into the name of the Father, and the Son, and the Holy Spirit. Truly, we know that the Ecclesia is Holy because it is God's Body and it deifies and nourishes all of us who are its members. The Universal (Katholikos) Body of Christ, being Apostolic, never wavers in its Faith, Doctrine, Hope, Unity, and Love (Agape="Service").
The Roman Catholic assemblies, along with all their offshoots, the Protestant confessions, cling to false teachers and foreign "doctrines" which are not of the Gospel of Christ Jesus. Many of them follow various hersies condemned by the Seven Ecumenical Councils, such as Filioquism, Nestorianism, Arianism, Gnosticism, Marcionism, Donatism, Nicolaitanism, Antinomianism, and Anthropo-Monarchianism (the belief that a mortal man can be the visible head of the Holy Ecclesia and that he could be considered "infallible".).
Until the heretical groups recant of each of those heresies that they individually practice, they will not be able to join with the visible One, Holy, Catholic, and Apostolic Ecclesia established in 33 AD by our Lord Jesus Christ. This is NOT TO SAY that we would think or preach that those persons, members of the aforementioned groups, who follow our Lord Jesus Christ, cannot be found having a Mystical Union with the Genuine Body of Christ merely due to their association, in ignorance, with a heretical group. We are admonished not to judge our brethren, lest we be judged! Of course, those of the heretical groups, who genuinely love our Lord Jesus Christ, being brought into illumination by our Faithful Brother and Sister servants, shall follow their instruction, based on the Agape of the Father, Son, and Holy Spirit, in harmony with the One Gospel of Christ Jesus to the Glory of God and the Defeat of the Evil One. Amen.
May the Grace of our Lord Jesus Christ, the Love of God the Father, and the Communion of the Good and Life-Creating Holy Spirit be with you all. Amen.