JL: Original sin is not an actual stain, it is a LACK of the indwelling life of God. Thru this LACK Man is subject to the flesh and all its desires. Man is born with a sin nature so to speak. We must be born again by water and Sprit, receiving the spiritual life of God the HS indwelling. The soul or spiritural nature, then rules over the flesh by the grace of the HS. That struggle between the flesh and spiritual within us is part of our spiritual warfare, we must always struggle to overcome the desires of the flesh, the spirit is willing but the flesh is weak. [Rm5:18 Then as ONE MAN’S TRESPASS led to CONDEMNATION for ALL MEN so one man’s act of righteousness leads to acquittal and life for all men 19 For as BY ONE MAN’S DISOBEDIENCE MANY WERE MADE SINNERS so by one man’s obedience many will be made righteous] Note, Condemnation for ALL men, MADE SINNERS, they did not commit personal sin, but WERE MADE SINNERS, bringing condemnation FOR ALL, by one man’s trespass.
[1Cor 7:14 For the unbelieving husband has been sanctified through his wife, and the unbelieving wife has been sanctified through her believing husband. OTHERWISE your CHILDREN would be UNCLEAN, but AS IT IS, THEY ARE HOLY.] So infants cannot be a Christian because they cannot DO, believe, repent. who gives that free gift of faith, doesn’t it come by God’s grace alone. God’s gift of saving grace is freely given by God, then comes what we must DO. It would seem you have left out one of the most important things they must DO, Christ tells us, you MUST be born again, and he tells us how, by water and the Spirit. Baptism brings a child into convenant family relationship with God, just as circumcision did in the old covenant, Paul makes that clear, with baptism being the circumcision of the heart. With your theory circumcision in the OT should have been only for adults. Because those OT adults had to have faith, repent and be circumcised to enter the people of God.