"And [Naaman] dipped himself . . . seven times in the Jordan [2 Kgs. 5:14]. It was not for nothing that Naaman of old, when suffering from leprosy, was purified upon his being baptized, but [this served] as an indication to us. For as we are lepers in sin, we are made clean, by means of the sacred water and the invocation of the Lord, from our old transgressions, being spiritually regenerated as newborn babes, 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 [John 3:5]" (Fragment 34 [A.D. 190]).

Infants are not baptized because they believe. They are baptized because of the clear Word, command and promise of God. They are baptized on account of God’s grace, not on account of their faith. Martin Luther writes, "For my faith does not constitute Baptism but receives it" (Tappert: p. 443).

Joh 3:5 Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God.
Joh 3:6 That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.

Gal 5:17 For the flesh  has desires against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that you may not do the things which you have a mind to do.

Rom 8:8 So then they that are in the flesh cannot please God.

Romans 3:23: for all have sinned and fall short of the glory of God.

1Pe 2:2 As newborn babes, desire the sincere milk of the word, that ye may grow thereby:

Dr. Martin Chemnitz: "Although we can neither understand nor explain in words what may be the nature of that action or operation of the Holy Spirit in infants who are baptized, nevertheless the Word of God leaves no doubt that such action and operation does occur. This which the Holy Spirit produces in infants we call faith and say that infants believe."

Dr. Johann Gerhard: "Even though we do not understand what all takes place with faith in the tiny, little children, yet we should hold the Word of God in such reverence that we do not deny what it so clearly witnesses to regarding the faith of little children."

Dr. David Scaer: "Surely, if infant brains can process human language and make sense out of their environment, they can process the divine language which proceeds from the mouth of God and calls to faith. It would be strange to assert that the words of the Holy Spirit lack the efficaciousness which human language has with infants."

Dr. William Arndt: “If the question is asked how an infant, unconscious of what is happening around it and unable to understand the meaning of Baptism, can believe, the answer is that not we but the Holy Spirit creates faith in the child receiving Holy Baptism and that He can perform that miracle and take up His dwelling in children as well as in people who are grown up.”

Dr. Robert Kolb: “The Word of God is powerful enough, when uttered, to change even a godless heart, which is no less responsive and helpless than any infant.”

Dr. Lowell Green: “God does not need human cooperation. In fact, faith is the setting aside of our own activity in order that God may work in us.”

"I have no taste for corruptible food nor for the pleasures of this life. I desire the bread of God, which is the flesh of Jesus Christ, who was of the seed of David; and for drink I desire his blood, which is love incorruptible" (Letter to the Romans 7:3 [A.D. 110]).

Tertullian

"[T]here is not a soul that can at all procure salvation, except it believe whilst it is in the flesh, so true is it that the flesh is the very condition on which salvation hinges. And since the soul is, in consequence of its salvation, chosen to the service of God, it is the flesh which actually renders it capable of such service. The flesh, indeed, is washed [in baptism], in order that the soul may be cleansed . . . the flesh is shadowed with the imposition of hands [in confirmation], that the soul also may be illuminated by the Spirit; the flesh feeds [in the Eucharist] on the body and blood of Christ, that the soul likewise may be filled with God" (The Resurrection of the Dead 8 [A.D. 210]).

Council of Ephesus

"We will necessarily add this also. Proclaiming the death, according to the flesh, of the only-begotten Son of God, that is Jesus Christ, confessing his resurrection from the dead, and his ascension into heaven, we offer the unbloody sacrifice in the churches, and so go on to the mystical thanksgivings, and are sanctified, having received his holy flesh and the precious blood of Christ the Savior of us all. And not as common flesh do we receive it; God forbid: nor as of a man sanctified and associated with the Word according to the unity of worth, or as having a divine indwelling, but as truly the life-giving and very flesh of the Word himself. For he is the life according to his nature as God, and when he became united to his flesh, he made it also to be life-giving" (Session 1, Letter of Cyril to Nestorius [A.D. 431]).