Barnabas wrote in 70 AD, “Blessed are they who, placing their trust in the cross, have gone down into the water; for, says He, they shall receive their reward in due time…we indeed descend into the water full of sins and defilement, but come up, bearing fruit in our heart, having the fear [of God] and trust in Jesus in our spirit.” (The Early Church Fathers: Ante-Nicene Fathers Volume 1, The Epistle of Barnabas 11:114-16)
Irenaeus wrote in 120-205 AD, “As we are lepers in sin, we are made clean from our old transgressions by means of the sacred water and the invocation of the Lord. We are thus spiritually regenerated as newborn infants, even as the Lord has declared: ‘Except a man be born again through water and the Spirit, he shall not enter into the kingdom of heaven.'”(Irenaeus, “Fragments From Lost Writings”, no. 34, Ante-Nicene Fathers, vol. 1, pg. 574)
The proof text that early Christians used for baptism was John 3:5!
In 110-165 AD, Justin Martyr wrote “they 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 ye be born again, ye shall not enter into the kingdom of heaven.‘ Now, that it is impossible for those who have once been born to enter into their mothers’ wombs, is manifest to all… And for this we have learned from the apostles this reason. Since at our birth we were born without our own knowledge or choice, by our parents coming together, and were brought up in bad habits and wicked training; in order that we may not remain the children of necessity and of ignorance, but may become the children of choice and knowledge, and may obtain in the water the remission of sins formerly committed” (Justin Martyr, “First Apology,” Ante-Nicene Fathers, vol. 1, pg. 183)
In 140-230 AD, Tertullian wrote, “Baptism itself is a corporal act by which we are plunged into the water, while its effect is spiritual, in that we are freed from our sins” (Baptism 7:2).
In 140-230 AD, Tertullian wrote, “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! A treatise on this matter will not be superfluous; instructing not only such as are just becoming formed in the faith… The consequence is, that a viper of the 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 and serpents themselves generally do affect arid and waterless places. (On Baptism, Ante-Nicene Fathers, vol. 3, pg. 669.)
Interesting in the prior quote is that there was a false teaching coming about that was denying baptism!
Tertullian also wrote, “The prescript is laid down that ‘without baptism, salvation is attainable by none’ chiefly on the ground of that declaration of the Lord, who says, ‘Unless one be born of water, he hath not life.'” (On Baptism, Ante-Nicene Fathers, vol. 3, pg. 674-675)
In 150-200 AD, CLEMENT wrote, “when you are regenerated and born again of water and of God, the frailty of your former birth, which you have through men, is cut off, and so at length you shall be able to attain salvation; but otherwise it is impossible. For thus hath the true prophet testified to us with an oath: ‘Verily I say to you, That unless a man is born again of water, he shall not enter into the kingdom of heaven.’ Therefore make haste; for there is in these waters a certain power of mercy which was borne upon them at the beginning…Betake yourselves therefore to these waters, for they alone can quench the violence of the future fire; and he who delays to approach to them, it is evident that the idol of unbelief remains in him, and by it he is prevented from hastening to the waters which confer salvation.” (Clement, “Recognitions of Clement,” Ante-Nicene Fathers, vol. 8, pg. 155)