BAPTISM OF JOHN. - It is the baptism that the precursor (whence the epithet "Baptist" = "baptizer") administered on the banks of the Jordan, inviting the people to change their lives and to prepare for the advent of the Kingdom of God (Mt. 3:5). Apparently it brought nothing new to the Jews, who already found prescribed in the Law (Lev. 14:1 ff., 15:5 ff.) several ablutions as rites of purification from legal impurity, and who knew the baptism of the Essenes, and perhaps also that of the proselytes, administered, after circumcision, to the gentiles who were being incorporated into Judaism. In reality, however, the baptism of John, as regards the rite and especially its moral significance, had certain notes of absolute novelty that distinguished it from every other.
1. John invokes a divine mandate for his work. To the Jews, in fact, who asked him: "Why do you baptize, if you are not the Christ nor a prophet?" he answers: "He who sent me to baptize in water," etc. (Jn. 1:33), and Jesus publicly confirms this divine origin (Mk. 11:30). 2. The baptism of the precursor has the wholly particular purpose of messianic preparation: "After me will come one who is greater than I, and I did not know him; but precisely for this I have come to baptize in water, so that he might be manifested in Israel" (Jn. 1:31; cf. also Acts 19:4). It is therefore a transitory rite, announcing a new order, entirely in function of the Jewish messianic expectation, so alive in those times that false Messiahs were not lacking. 3. From what has been said the difference between the baptism of the precursor and the others appears easily. It is distinguished: a) from the ablutions imposed by the Law, because these each person performed for himself and they conferred only a legal, exterior purity; b) from the baptism of the proselytes, because this was administered only to gentiles and brought about nothing but a ritual purification, whereas the baptism of John was given also to the Israelites themselves and had reference to the remission of sins; c) from the baptism of the Essenes, because this was repeated many times, had no reference whatever to the restoration of the Kingdom of God, and did not bring about nor signify a full interior renewal.
The baptism of John, moreover, differs specifically from Christian Baptism: a) in origin, because it was not instituted by Jesus Christ; b) in the exterior act that constitutes it, because it consists only in the application of the matter, without any form being added; in its significative power, because it signifies not the grace presently given but the future grace that Jesus would merit for us by his passion and death; in its causal power. The baptism of John did not act ex opere operato, like the Sacrament, that is, producing what it signifies, namely the remission of guilt and the conferral of grace; but only ex opere operantis, disposing through works of penance; and finally, the Christian rite regenerates the one who receives it, imprints on his soul an indelible character, introduces him into the society founded by Christ, makes him capable of receiving the other Sacraments; all effects that the baptism of the precursor was incapable of producing (cf. H. Houbant, Jean B. [baptême de], in DThC, VIII, col. 655).
John, moreover, is explicit on this point: "I have baptized you in water; but he will baptize you in the Holy Spirit" (Mk. 1:8), "in the Holy Spirit and fire" (Mt. 3:11; Lk. 3:16), where the addition "fire" indicates that the grace given by Baptism will consume sins like fire, will purify and enlighten. The divine agent, who is the Holy Spirit, is at the service only of the Messiah. For their part the Apostles, from the very first moment of their preaching, considered the baptism of John as nonexistent and baptized "in the name of Jesus" all who presented themselves, even those who had already previously been baptized by the precursor (Acts 2:38; 19:1-7); because Jesus' peremptory command was directed to all without exception (Mt. 18:19). Therefore the Church, once the errors of the so-called reform had arisen, defined at the Council of Trent: "If anyone asserts that the baptism of John had the same efficacy as that of Jesus, let him be anathema" (Sess. VII, de Bapt., can. 1: Denz-U, n. 857).