Roman Catechism 17.25

Chapter 17 — Part II: The Sacraments — Confirmation

Section 25. The thorough propriety of reserving this function to Bishops the pastor may illustrate by the following comparison. As in the construction of buildings the artisans, who are inferior agents, prepare and dispose cement, lime, timbers and the other material, while to the architect belongs the completion of the work; so in like manner this Sacrament, which is, at it were, the completion of the spiritual edifice, should be performed by no other than the chief priest.