Introduction:

The Roman Catholic Church teaches that "Baptism by water (Baptismus fluminis) is, since the promulgation of the Gospel, necessary for all men without exception, for salvation" (Ott, 356).

In other words, the Church teaches that Baptism by water is a medial necessity for salvation. It should also be added that the Church holds that in a case of emergency Baptism by water can be replaced by Baptism of desire or Baptism by blood if certain conditions are met (Ott, 356). Now where does this idea of Baptism as a medial necessity for salvation arise from? The answer, in short, is that the Church bases, in large part, Her teaching on Baptism by water as a medial necessity for salvation, upon John 3:5 - "Amen, amen, I say to thee, unless a man be born again of water and the Spirit, he cannot enter into the kingdom of God." In the early centuries of the Church this text was interpreted to mean (1) that Baptism by water is necessary for salvation, and (2) that Baptism by water is regenerative in its effect (i.e., the Sacrament of Baptism communicates to the baptized, through grace, a participation in the Divine Life such that the baptized now lives by a supernatural life principle which he, before Baptism, did not possess [Ott, 256]). In this essay I intend to view the manner in which this twofold Johannine meaning of Baptism played itself out in early conciliar and non-conciliar documents.
 

Early Church Non-Conciliar Use of John 3:5:

Many Early Church Fathers have commented on John 3:5 and have affirmed the medial necessity of Baptism by water as well as the regenerative nature of Baptism. However, we shall only look at the testimony of two such Fathers, namely, St. Irenaeus and St. Augustine.

St. Irenaeus is a second century Church Father who describes the nature and necessity of Baptism by water in his famous First Apology (written about 155 AD). In this document he has the following to say about Baptism by water:

St. Augustine is another Early Church Father who comments upon the nature of Baptism and its connection with Johannine theology. In his Tractate 11, of his Commentary on St. John's Gospel, St. Augustine comments that John 3:5 refers to Baptism as a means whereby one is spiritually regenerated. In addition to this St. Augustine also holds that implicit in the nature of Baptism is the doctrine that it can only be received once. That is, since by Baptism one is spiritually regenerated or born again, and since one can be born only once (as in the case of natural birth), it follows that one can be regenerated or born again through Baptism only once.

Thus, St. Augustine holds that this doctrine, which holds that Baptism can only be received once, is implicit in John 3:5. Also, in his work De Symbolo ad Catechumenos, St. Augustine holds that the regenerative nature of Baptism is efficacious in its remission or forgiveness of sins. In other words, St. Augustine is teaching that in the same moment that one comes to participate in God's Life, via grace, one is also washed clean of all sin. Furthermore, both in De Symbolo ad Catechumenos and in his De Fide et Symbolo (ch. 1), St. Augustine teaches that in the creed the statement about Baptism and the remission of sins ought to fall under the section in the creed concerning the Holy Spirit. This strategic placement of the creedal statements on Baptism and the remission of sins seems to be very fitting if it is seen in light of his above noted commentary on John 3:5. For, since one is regenerated by water and the Holy Spirit in Baptism it seems supremely fitting to place the creedal statement on Baptism and the remission of sins under the section of the creed concerning the Holy Spirit. Moreover, it is important to note that the "creed" upon which St. Augustine was commenting was an early form of the Nicene-Constantinopolitan Creed which would be formally defined in 381AD (see DS 2).
 

Early Church Conciliar Use of John 3:5:

As mentioned above, the placement of the statement, "I confess one baptism for the remission of sins," (DS, 86) in the Nicene-Constantinopolitan Creed seems to reflect, according to St. Augustine, a certain Patristic reading of John 3:5. St. Irenaeus, St. Augustine, as well as numerous other Fathers of the Church, recognized that John 3:5 teaches that Baptism by water is both necessary and is spiritually regenerative. In being spiritually regenerative Baptism remits the sins of its recipient. These Fathers, especially St. Augustine, also recognize that this spiritual regeneration is effected by the three Persons of the Blessed Trinity Who act in common as One Principle. However, this work of sanctification is fittingly appropriated to God the Holy Spirit insofar as sanctification is an act of divine love and insofar as God the Holy Spirit is the Infinite Personal Divine Love of God the Father and God the Son (De Trinitate, 15: 29, 31). As a result of this, we can see that the very placement of the creedal statement on Baptism, under the creedal statements on the Holy Spirit, is of Johannine influence. This Johannine influence is rather implicit, though, and is hard to recognize unless one first views the way in which the Early Church Fathers saw the creed as being profoundly Trinitarian in its outline, as well as the ways in which they interpret St. John's Gospel and draw their theological conclusions from it.

Besides the Council of Constantinople the baptismal Theology of John 3:5 doesn't seem to make any other appearances in the Early Church Councils with which we are concerned here. It does, however, find explicit mention and commentary in numerous Papal and Conciliar documents stretching from the fifth to the sixteenth centuries. I list here some of the chief documents for the readers interest:
 

Papal and Conciliar Commentaries:

(1) Pope St. Zosimus's approval of the Council of Mileum II (416), canon 3. (DS 102n).

(2) Council of Valence III (855), canon 5. (DS 324).

(3) Pope Innocent III's Letter "Ex parte tua" (1206). (DS 410).

(4) Pope Innocent III's Letter "Non ut apponeres" (1206). (DS 412).

(5) Pope Gregory IX's Letter "Cum, sicut ex" (1241). (DS 447).

(6) Council of Florence "Decree for the Armenians" (1439). (DS 696).

The Council of Trent:

The documents from the Council of Trent (1545-1563) are of great importance for understanding the way in which John 3:5 has been appropriated, interpreted, and understood in Catholic Theology of Baptism. For, it is in these conciliar documents that Catholic Theology of Baptism reaches its doctrinal summit and it is also in these documents that the various Patristic theological insights on John 3:5 are woven together into one theological fabric.

The Council of Trent appealed to John 3:5 in two of its decrees and in one of its dogmatic canons. Here I quote the relevant texts in full:

(1) Decree on Original Sin, canon 4: "If anyone denies that infants newly born from their mothers' womb are to be baptized," even though they be born of baptized parents, "or says they are baptized indeed for the remission of sins, but that they derive nothing of original sin from Adam, which must be expiated by the laver of regeneration" for the attainment of life everlasting, whence it follows, that in them the form of baptism for the remission of since is understood to be not true, but false: let him be anathema. For what the Apostle has said: "By one man sin entered into the world, and by sin death, and so death passed upon all men, in whom all have sinned" (Rom. 5:12), is not to be understood otherwise than as the Catholic Church spread everywhere has always understood it. For by reason of this rule of faith from a tradition of the apostles even infants, who could not as yet commit any sins of themselves, are for this reason truly baptized for the remission of sins, so that in them there may be washed away by regeneration, what they have contracted by generation. "For unless a man be born again of water and the Holy Ghost, he cannot enter into the kingdom of God" (John 3:5) (DS, 791).

(2) Decree on Justification, chapter 4: "In these words a description of the justification of a sinner is given as being a translation from that state in which man is born a child of the first Adam to the state of grace and of the "adoption of the sons" (Rom. 8:15) of God through the second Adam, Jesus Christ, our Savior; and this translation after the promulgation of the Gospel cannot be effected except through the laver of regeneration, or a desire for it, as it is written: "Unless a man be born again of water and the Holy Ghost, he cannot enter into the kingdom of God" (John 3:5) (DS, 796).

(3) Canons on the Sacrament of Baptism, canon 2: "If anyone shall say that real and natural water is not necessary for baptism, and on that account those words of our Lord Jesus Christ: "Unless a man be born again of water and the Holy Ghost" (John 3:5) are distorted into some sort of metaphor: let him be anathema (DS, 858).

• The Quotation from St. Irenaeus' First Apology is from Cyril Richardson, Early Christian Fathers.
• Citations from St. Augustine's works are from http://www.newadvent.org/fathers/
• Citations of conciliar documents are from Henry Denzinger, The Sources of Catholic Dogma.
• References in the introduction, to Catholic doctrine on Baptism, are from Ludwig Ott, Fundamentals of Catholic Dogma.