Roman Catechism 15.1

Chapter 15 — Part II: The Sacraments — Introduction on the Sacraments in General

Section 1. Importance Of Instruction On The Sacraments — The exposition of every part of Christian doctrine demands knowledge and industry on the part of the pastor. But instruction on the Sacraments, which, by the ordinance of God, are a necessary means of salvation and a plenteous source of spiritual advantage, demands in a special manner his talents and industry By accurate and frequent instruction (on the Sacraments) the faithful will be enabled to approach worthily and with salutary effect these inestimable and most holy institutions; and the priests will not depart from the rule laid down in the divine prohibition: Give not that which is holy to dogs: neither cast ye your pearls before swine.