Chapter 21 — Part II: The Sacraments — Holy Orders
Section 69. Hence we readily understand why it is that ordinations take place only on special days, on which, moreover, in accordance with a very ancient practice of the Catholic Church, a solemn fast is appointed in order that by holy and fervent prayer the faithful may obtain from God ministers who will be well qualified to exercise properly and to the advantage of the Church the power of so great a ministry.