Christians have always interpreted the Bible literally when it declares,
"Baptism . . . now saves you, not as a removal of dirt from the body, but as an appeal to God for a clear conscience, through the resurrection of Jesus Christ" (1 Pet. 3:21; cf. Acts 2:38, 22:16, Rom. 6:3–4, Col. 2:11–12).
Thus the early Church Fathers wrote in the Nicene Creed (A.D. 381), "We believe in one baptism for the forgiveness of sins."
And the Catechism of the Catholic Church states:
"The Lord himself affirms that baptism is necessary for salvation [John 3:5]. . . . Baptism is necessary for salvation for those to whom the Gospel has been proclaimed and who have had the possibility of asking for this sacrament [Mark 16:16]" (CCC 1257).
The Christian belief that baptism is necessary for salvation is so unshakable that even the Protestant Martin Luther affirmed the necessity of baptism. He wrote: "Baptism is no human plaything but is instituted by God himself. Moreover, it is solemnly and strictly commanded that we must be baptized or we shall not be saved. We are not to regard it as an indifferent matter, then, like putting on a new red coat. It is of the greatest importance that we regard baptism as excellent, glorious, and exalted" (Large Catechism 4:6).
Yet Christians have also always realized that the necessity of water baptism is a normative rather than an absolute necessity. There are exceptions to water baptism: It is possible to be saved through "baptism of blood," martyrdom for Christ, or through "baptism of desire", that is, an explicit or even implicit desire for baptism.
Thus the Catechism of the Catholic Church states: "Those who die for the faith, those who are catechumens, and all those who, without knowing of the Church but acting under the inspiration of grace, seek God sincerely and strive to fulfill his will, are saved even if they have not been baptized" (CCC 1281; the salvation of unbaptized infants is also possible under this system; cf. CCC 1260–1, 1283). (no one can consciously commit the sin of Adam, so you do not need informed consent to have it removed in baptism)
As the following passages from the works of the Church Fathers illustrate, Christians have always believed in the normative necessity of water baptism, while also acknowledging the legitimacy of baptism by desire or blood.
Hermas
"‘I have heard, sir,’ said I [to the Shepherd], ‘from some teacher, that there is no other repentance except that which took place when we went down into the water and obtained the remission of our former sins.’ He said to me, ‘You have heard rightly, for so it is’" (The Shepherd 4:3:1–2 [A.D. 80]).
Justin Martyr
"As many as are persuaded and believe that what we [Christians] teach and say is true, and undertake to be able to live accordingly . . . are brought by us where there is water, and are regenerated in the same manner in which we were ourselves regenerated. For, in the name of God, the Father and Lord of the universe, and of our Savior Jesus Christ, and of the Holy Spirit, they then receive the washing with water. For Christ also said, ‘Except you be born again, you shall not enter into the kingdom of heaven’ [John 3:3]" (First Apology 61 [A.D. 151]).
Tertullian
"Happy is our sacrament of water, in that, by washing away the sins of our early blindness, we are set free and admitted into eternal life. . . . [But] a viper of the [Gnostic] Cainite heresy, lately conversant in this quarter, has carried away a great number with her most venomous doctrine, making it her first aim to destroy baptism—which is quite in accordance with nature, for vipers and asps . . . themselves generally do live in arid and waterless places. But we, little fishes after the example of our [Great] Fish, Jesus Christ, are born in water, nor have we safety in any other way than by permanently abiding in water. So that most monstrous creature, who had no right to teach even sound doctrine, knew full well how to kill the little fishes—by taking them away from the water!" (Baptism 1 [A.D. 203]).
"Without baptism, salvation is attainable by none" (ibid., 12).
There are 10 more consistent quotes here, going from the 2nd to the 5th century:
http://www.catholic.com/library/Nece...of_Baptism.asp
There are many more.
Regenerative baptism was taught by Jesus and the Aposltes, pre-dates the canon of the Bible and the evidence is there for anyone who WANTS to see it.