Chapter 15 — Part II: The Sacraments — Introduction on the Sacraments in General
Section 66. First Effect: Justifying Grace — The principal effects of the Sacraments are two. The first place is rightly held by that grace which we, following the usage of the holy Doctors, call sanctifying. For so the Apostle most clearly taught when he said: Christ loved the church, and delivered himself up for it; that he might sanctify it, cleansing it by the laver of water in the word of life. But how so great and so admirable an effect is produced by the Sacrament that, to use the well-known saying of St. Augustine, water cleanses the body and reaches the heart, -- this, indeed, cannot be comprehended by human reason and intelligence. It may be taken for granted that no sensible thing is of its own nature able to reach the soul; but we know by the light of faith that in the Sacraments there exists the power of almighty God by which they effect that which the natural elements cannot of themselves accomplish.