Roman Catechism 16.36

Chapter 16 — Part II: The Sacraments — Baptism

Section 36. Institution Of Baptism — When these things have been explained, it will also be expedient to teach and remind the faithful that, in common with the other Sacraments, Baptism was instituted by Christ the Lord. On this subject the pastor should frequently teach and point out that there are two different periods of time which relate to Baptism, -- one the period of its institution by the Redeemer; the other, the establishment of the law regarding its reception.