Here is a stern requisition against a muddled ecclesiology of our days written by a lay theologian, known for his Akribia.
In the light of the patristic teaching there is no Church but One Church and Her boundaries on Earth coincide with the visible Eucharist of the Orthodox.
Sentimental ecumenicist ecclesiology undermines this clear self-understanding of the Holy Tradition.
One may disagree with the Author, but his arguments remain unassailable.
(This English version is published by Holy Transfiguration Monastery, Boston, Mass. USA /1967/).