What is the Biblical basis for the Catholic teaching that infant baptism cleanses from original sin?

It is important to understand what 'Sin' is and how the Early church lived and what is the orthodox teaching. First of all, sin in greek means 'missing the target'; Sin has no existence at all. The Church Fathers are consistent in this regard. Sin is a disease it is a sickness that affects all ...

"for unless we say the flesh was capable of receiving the things which belonged to it, with the exception of sin - for this is NOT part of the ousia, but a sickness which, as I have said, occurs as a result of inattention.." - St.Severus of Antioch

Because sin is nothing in essence and has no existence, it can NOT be part of our nature. Sin is only a sickness, it is missing the target (of course our target is Christ and his recapitulated life here on earth). Understanding this is important if one was to understand what sin means according the Fathers. Sin can not be past from parents to children, simply because it doesn't exist; it is not part of our nature. Man is by nature corruptible and mortal, not, man's nature is sinful (nature here of course meaning in the essence of Humanity). I could add in more quotes by other Church Fathers but i'll try to be as short as I can.

Another important point to make is that condition and nature are not the same. Man was always by nature mortal and corruptible because he came into being from nothing (St.Athanasius and St.Severus). But because God granted him a grace (to live in a CONDITION that is ABOVE his natural state and that transcends his natural state, he was able to share (through external participation (grace) NOT in essence with God's immortality and incorruptibility)). That does NOT mean man's nature changed .. No! Nature does not change. A chicken's nature that doesn't change into a horse nature, nor does a man's nature changes.But the condition changed .. Adam lived in a condition that was ABOVE is natural being, but that was only a grace given by God. Therefore when adam sinned, his nature did not changed (he was always mortal and corruptible) but his condition changed, ie. He went back to his original state and lived in that condition that is matching with his nature ...

"This, then, was the plight of men. God had not only made them out of nothing, but had also graciously bestowed on them His own life by the grace of the Word. Then, turning from eternal things to things corruptible, by counsel of the devil, they had become the cause of their own corruption in death; for, as I said before, though they were by nature subject to corruption, the grace of their union with the Word made them capable of escaping from the natural law, provided that they retained the beauty of innocence with which they were created." - St.Athanasius, on the Incarnation

And ...

"If however, he had continued to maintain his vision of God, he would have transcended the natural corruptibility and remained incorruptible" – St.Severus of Antioch

All this was just to introduce the idea that sin, has no essence, and is nothing. Thus I ask ..Can we move darkness?? ofcourse not .. why? because it does not exist (it is the lack of light!) but conversely I ask, can we move light? Yes we can, as light in essence is made up of photons, packets of energy, etc. Therefore as sin is nothing and can NOT be part of our nature as the Holy fathers of the early church taught us, then it can not be transmitted, let alone through sex.

Moreover, in Psalm 51, the following is read .. "and in sinS did my mother conceive me". This is the ORGINAL translation found in the septuagint LXX. It is clear that it is sins (plural) not sin (singular). The jewish Scholars knew what they were doing when they translated the hebrew into greek. David the prophet here is NOT talking about a specific form of sin that we are born with that has been passed onto us from our parents, but rather he is talking about the sinful experience that our parents are passing unto us and that we will pass unto our children. Since the Septuagint has sins and not sin, it clarifies what David the prophet meant; sins are endemic to humanity.

Last but not least, our church Fathers are very clear about how we are born ..

"The sin of those who engendered us, viz. the sin of Adam and Eve, is NOT NATURALLY MIXED WITH OUR SUBTANCE, as the evil and impious opinion of the Messalians ... we are born mortal insofar as we are born of mortal parents, but NOT sinners insight as we of sinful parents. For IT IS NOT TRUE that sin is a NATURE and THAT IT NATURALLY PASSED FROM PARENTS TO THEIR CHILDREN" - St.Severus of Antioch

WE inherit the condition and the consequence of the original sin, we are still born dead (separation from the source of life), but we are not born sinners, baptism is the remission of sins of course, but baptizing infants is allowing them to die WITH christ and rise anew, being the abode of the holy spirit; St. John Chrysostom teaches us ...

" For this reason we baptize even infants, though they are sinless, so that there may be given to them holiness, righteousness, adoption, inheritance, brotherhood with Christ, and that they may be his [Christ’s] members".

We are born mortal nor sinful, we baptize infants even though they are sinless in order to give them the trinity and the seal of the Holy Spirit (St.Gregory the Theologian).

The only recorded connection between original sin and baptism appears to be in the Catechism of the Catholic Church

Born with a fallen human nature and tainted by original sin, children also have need of the new birth in Baptism to be freed from the power of darkness... CCC 1250

However, I can find no connection in scripture between the two, not during the time of Christ nor later. Saint Paul is the very first to make a connection between Original Sin and Adam in his Roman Epistle (Romans 5:12-21), but neither he, Christ nor the original apostles draw any connection between baptism and original sin within canonical gospel. Moreover, Saint Augustine muddies the water further by stating that those born of baptized parents have no need to be baptized:

1. In three ways then are sins remitted in the Church; by Baptism, by prayer, by the greater humility of penance; yet God does not remit sins but to the baptized. The very sins which He remits first, He remits not but to the baptized. When? When they are baptized. The sins which are after remitted upon prayer, upon penance, to whom He remits, it is to the baptized that He remits. For how can they say, "Our Father," who are not yet born sons? The Catechumens, so long as they be such, have upon them all their sins. If Catechumens, how much more Pagans? How much more heretics? But to heretics we do not change their baptism. Why? Because they have baptism in the same way as a deserter has the soldier's mark: just so these also have Baptism; they have it, but to be condemned thereby, not crowned. And yet if the deserter himself, being amended, begin to do duty as a soldier, does any man dare to change his mark?

A Sermon to Catechumens on the Creed, Paragraph 16

It's clear that the above Catechism reference was certainly required as clarification. However, it remains that there is no scriptural source for any direct association between original sin and a subsequent requirement for baptism.

Also, the use of David's Psalm 51:5 in this argument is unjustified. The Psalms were composed by David while he was a wanted fugitive running from King Saul. It was common practice in ancient times (to some extent today) to blame all misfortune on sin or wickedness. Therefore, no further expansion was made of this within Jewish worship. Subsequently, Original Sin is not contained within the Jewish Talmud.

Catholic church believes that among other things, baptism is for remission of sins both original as well actual. Original in case of infants and original as well as actual in case of adults.

Baptism removes original sin:

Baptism is closely related to regeneration or ‘Born again” which is the transformation from death to life that occurs in our souls when we first come to God and are justified. He washes us clean of our sins (original as well as actual) as Psalm 51 points out:

Psalm 51:5 Look, I was guilty of sin from birth, a sinner the moment my mother conceived me.

Baptism gives us a new nature, breaking the power of sin over us, so that we will no longer be its salves but its enemies who must fight it as part of Christian life (Rom. 6:1-22; Eph. 6:11-17).

Jesus taught of this transformation through baptism of water and Spirit in John 3:5. In the water-and-Spirit rebirth that takes place at baptism, we are transformed from state of sin to the state of grace.

Peter mentioned this transformation from state of sin to grace when he exhorted people in Acts. 2:38-39.

Acts 2:38 Repent, and be baptised every one of you in the name of Jesus Christ for forgiveness of your sins; and you shall receieve the gift of the Holy Spirit'

and

Acts 2:39, For the promise is to you and to your children and to all that are far off, every one whom the Lord out God calls to him'

Peter explains the removal of original sin from our nature:

1 Pet. 3:20-21 ‘After they were disobedient long ago when God patiently waited in the days of Noah as an ark was being constructed. In the ark a few, that is eight souls, were delivered through water. 3:21 And this prefigured baptism, which now saves you – not the washing off of physical dirt but the pledge of a good conscience to God – through the resurrection of Jesus Christ,

Furthermore Paul notes that baptism has replaced circumcision.

In Col. 2:11 In him you also were circumcised – not, however, with a circumcision performed by human hands, but by the removal of the fleshly body, that is, through the circumcision done by Christ. 2:12 Having been buried with him in baptism, you also have been raised with him through your faith in the power of God who raised him from the dead.

If Paul meant to exclude infants, he would not have chosen circumcision as a parallel for baptism.

Augustine also taught that,

“ It is this one Spirit who makes it possible for an infant to be regenerated ... when that infant is brought to baptism; and it is through this one Spirit that the infant so presented is reborn. For it is not written, ‘Unless a man be born again by the will of his parents’ or “ by the faith of those born again of water and the Holy Spirit’[John3:5]. The water, therefore manifesting exteriorly the sacrament of grace, and the Spirit effecting interiorly the benefit of grace, both regenerate in one Christ that man who is generated in Adam”(Letters 98:2)

Origen also wrote in the third century that 'according to the usage of Church, baptism is given even to infants'(Homilies on Leviticus, 8:3:11,AD 244).

The council of Carthage, in 253, condemned the opinion that baptism should be witheld from infants until the eight day after birth.

Later Augustine taught,'The custom of Mother Church in baptising infants is certainly not to be scorned ....nor is to be believed that its tradition is anything except apostolic' (Literal Interpretation of Genesis 10:23:39, AD 408)

For us Catholics our believe is that original sin came into being through the fall of one man(Adam) and through the only lamb of GOD(JESUS) who washes away the sins of the whole world with his death and resurrection on mount Calvary mankind was restored and have redemption which includes free from original sin too. And now scripture have it that who so ever confesses with the lips and believed with the heart that Jesus Christ is Lord shall be free indeed. And also the infant baptism is given to the child base on the faith of the parents that they will nurture the life that God has entrusted to them.