The First Mark: One

The Church is one. The Catechism notes that the Church is one for three reasons: first, because of its source, which is the Holy Trinity, a perfect unity of three divine persons — Father, Son, and Holy Spirit; second, because of its founder, Jesus Christ, who came to reconcile all mankind through the blood of the cross; and third, because of its "soul," the Holy Spirit, who dwells in the souls of the faithful, who unites all of the faithful into one communion of believers, and who guides the Church (#813). The "oneness" of the Church is also visible. Catholics are united in the Creed and the other teachings, the celebration of the sacraments, and the hierarchical structure based on the apostolic succession preserved and handed on through the Sacrament of Holy Orders. For example, no matter where a Catholic celebrates Mass, the Mass is the same — the same readings, structure, and prayers. Another place the oneness of the Church is present is the diversity of the Church. Lots of different people in lots of different cultures and traditions celebrate Catholicism. Although there is lots of diversity in the Catholic Church, all the members in the Church are united. The oneness of the Church has allowed the members of the Catholic Church to stay united for centuries.