Dr. Alexander Kalomiros wrote a very important book against the heresy of ecumenism, titled Against False Union. In it, Dr. Alexander makes a very necessary word that is, in our day and age, constantly being redefined: the word catholic. A truly Orthodox definition of this word refers to a local Orthodox church, regardless of size or who it may or may not be in communion with. The Orthodox Church does not need “external bonds to be one.” Sadly, this idea has crept into the New Calendarists, who claim that since we Old Calendarists/Genuine Orthodox are not in communion with the Ecumenical Patriarch, we are schismatic. This is a very papal (and hence, foreign) concept to the Orthodox Church. When a bishop ceases to teach the Orthodox faith, Orthodox Christians have a duty to separate from that bishop to preserve the True Faith.
A local Orthodox church regardless of her size or the number of the faithful is by herself alone, independently of all the others, catholic. And this is so because she lacks nothing of the grace and gift of God. All the local churches of the whole world together do not contain anything more in divine grace than that small church with few members.
The Orthodox people must become conscious of the fact that they owe no obedience to a bishop, no matter how high a title he holds, when that bishop ceases being Orthodox and openly follows heretics with pretenses of union “on equal terms.” On the contrary, they are obliged to depart from him and confess their Faith, because a bishop, even if he be patriarch or pope, ceases from being a bishop the moment he ceases being Orthodox.