Chapter 16 — Part II: The Sacraments — Baptism
Section 33. Whichever of these rites be observed, we must believe that Baptism is rightly administered. For in Baptism water is used to signify the spiritual ablution which it accomplishes, and on this account Baptism is called by the Apostle a laver. Now this ablution is not more really accomplished by immersion, which was for a considerable time the practice in the early ages of the Church, than by infusion, which we now see in general use, or by aspersion, which there is reason to believe was the manner in which Peter baptised, when on one day he converted and gave Baptism to about three thousand souls.