CCC 1593
Christian Mystery›SECTION TWO THE SEVEN SACRAMENTS OF THE CHURCH›CHAPTER THREE THE SACRAMENTS AT THE SERVICE OF COMMUNION›IN BRIEF
Since the beginning, the ordained ministry has been conferred and exercised in three degrees: that of bishops, that of presbyters, and that of deacons. the ministries conferred by ordination are irreplaceable for the organic structure of the Church: without the bishop, presbyters, and deacons, one cannot speak of the Church (cf St. Ignatius of Antioch, Ad Trall. 3,1).