On Oneness

The presence of human imperfection among her members is powerless to obliterate the unity, for Christ Himself promised that the "gates of hell shall not prevail against the Church." Satan has always sown tares in the field of the Lord and the forces of disunity have often threatened but have never actually succeeded in dividing the Church. No power can be mightier than the omnipotent will of Christ Who founded one Church only in order to bring men into unity with God. Oneness is an essential mark of the Church.
Oberlin Statement of Orthodox - North American Faith and Order Study Conference