The Catechism of St. Thomas Aquinas
THE EFFECT OF BAPTISM
The effect of Baptism is to remit both original and actual sin as well as all guilt and punishment which they incur. No kind of punishment must be enjoined for past sins upon those just newly baptized. Hence, those who die immediately after Baptism are admitted to the glory of God without delay. The effect, therefore, of Baptism is the opening of the gates of paradise.
ERRORS CONCERNING BAPTISM
There have been certain errors concerning this Sacrament. The first was that of the Solentiani, who received a baptism not of water but of the spirit. Against them the Lord says: “Unless a man be born again of water and the Holy Spirit, he cannot enter into the kingdom of God.” The second error was that of the Donatists, who re-baptized those who had been baptized by the Catholics. Against them it is written: “One faith, one baptism.” They also err in holding that a man in the state of sin cannot baptize. Against them it is said: “He upon whom thou shalt see the Spirit descending, and remaining upon Him, He it is that baptizeth.” It is thus seen that a minister who is himself evil does not invalidate either this or any of the other Sacraments, because it is Christ who, by the merits of His
passion, gives to each Sacrament its efficacy; and He is good. The fourth error is that of the Pelagians who say that children must be baptized because by their regeneration they, as adopted children of God, are admitted into the kingdom, but by this regeneration they are not freed from original sin.
14. The priest is the ordinary minister of Baptism. In case of necessity, however, anyone who observes the proper form and intention can baptize validly but not licitly; and an adult who permits himself to be baptized without necessity by a layman would be acting illicitly, but the baptism is valid. For such conduct places an “obex” (obstacle or hindrance) to the reception of grace. The grace of the Sacrament is revived (“reviviscitur”) with at least contrition, and probably attrition, or simply by an act of perfect contrition.
15. John. iii. 5
16. Eph., iv. 5.
17. John. i. 33