“The Church of Christ is One, Holy, Universal and Apostolic. She is herself a single spiritual body, whose head is Christ, and who has the one Holy Spirit abiding in her. The local parts of the Church are members of a single body of the Universal Church, and they, like branches of a single tree, are nourished by one and same sap from a single root. She is called holy because she is sanctified by the holy word, deeds, sacrifice and suffering of her founder, Jesus Christ, to which end He came in order to save human beings and lead them to holiness. The Church is called universal because she is not confined by place, not by time, nor by nation nor language. The Church communicates with all humanity. The Orthodox Church is called apostolic because the spirit, teaching and labors of the Apostles of Christ are entirely preserved in her.”
(St. Nicholas of Velimirovich, Catechesis)