The Moscow Patriarchate’s rejection of an errant ecumenism:
‘The essential goal of relations between the Orthodox Church and other Christian confessions is the restoration of that unity among Christians which is required of us by God (Jn. 17:21). Unity is part of God's design and belongs to the very essence of Christianity. It is a task of the highest priority for the Orthodox Church at every level of her life. Indifference to this task or its rejection is a sin against God's commandment of unity. According to St. Basil the Great, “all who are really and truly serving the Lord should have this one aim—to bring back into union the Churches that have been severed from one another” (Letter 114).
Nevertheless, while recognising the need to restore our broken Christian unity, the Orthodox Church asserts that genuine unity is possible only in the bosom of the One, Holy, Catholic and Apostolic Church. All other “models” of unity seem to us to be unacceptable.
The Orthodox Church cannot accept the assumption that despite the historical divisions, the fundamental and profound unity of Christians has not been broken and that the Church should be understood as coextensive with the entire “Christian world,” that Christian unity exists across denominational barriers and that the disunity of the churches belongs exclusively to the imperfect level of human relations.
According to this conception, the Church remains one, but this oneness is not, as it were, sufficiently manifest in visible form. In this model of unity, the task of Christians is understood not as the restoration of a lost unity but as the manifestation of an existing unity.
This model repeats the teaching on “the invisible Church” which appeared during the Reformation. The so-called “branch theory”, which is connected with the conception referred to above and asserts the normal and even providential nature of Christianity existing in the form of particular “branches,” is also totally unacceptable.’
–Basic Principles of the Attitude of the Russian Orthodox Church Toward the Other Christian Confessions (ratified in August 2000 at the Jubilee Bishops’ Council)