Conclusion

No incident is recorded in the earliest of Christian history which gives evidence that baptism was forbidden to any person on the basis of an age limit, or that the right of a Christian parent to have his children baptized had ever been challenged or renounced.

Although several examples exist from the third century of the children of Christians being baptized as infants, in all of the literature and collections of inscriptions from that century there is not a single example of Christian parents delaying the baptism of their children.

Neither the Ebionites, Novatians, Arians, Donatists, Montanists, nor any other early heresy refuted infant baptism; many were even noted as practicing it.
A significant parallel exists between Jewish proselyte baptism (when pagans were converted to Judaism) and early Christian baptism. The contacts between early Christian baptism and proselyte baptism, with the similarities in terminology, interpretation, symbolism, and the rite itself, are especially notable. What is of greatest interest, however, is that the baptism of the early Church followed that of proselyte baptism, in which children and infants were baptized with the convert's family. This is especially significant when one realizes that the very early Church was made up primarily of converted Jews.

If infant baptism is a later invention, when did it begin and who began it? Where did it originate?
Why are there no protests against the validity of infant baptism from anyone in the early Church?
Where is anything found in Scripture that expressly forbids the baptism of infants or children?
How is it that God established a covenantal, corporate relationship with the tribes of Israel in the Old Testament, but you interpret the New Testament as abolishing the faith of an entire household with the father at its head in favor of a solely individualistic faith?
Where does Scripture prescribe any age for baptism?
Even if there were a special age when someone's faith reached "maturity," how could one discern that? Doesn't faith always mature? When is faith mature enough for baptism and when is it not? Who can judge?
Where in Scripture does it say that children are free from the effects of the Fall simply because they are not old enough to believe? (Even creation is under the curse of mankind's fall - Romans 8:19-21).
What about the many Biblical meanings and early Christian understandings of baptism other than the one defining it as a visible sign of inward repentance, meanings such as the sacrament of regeneration (Titus 3:5), a grafting into the body of Christ (1 Corinthians 12:13), a passage from the reign of Satan into Christ's authority (Romans 6:17), the expression of the manifestation of God (Luke 3:21,22), an admission into God's covenant (Colossians 2:11), the Lord's act of adoption and our putting on of Christ (Galatians 3:26,27)? Why should these things be taken away from the small child of a Christian family?
If it was the norm to baptize children at a later age, why is there no evidence in Scripture or early Church history of instruction given to parents on how to help their adolescent children prepare for baptism?
If it is granted that baptism is for the remission of sins, why would the Church ever want to give baptism to infants if there were nothing in the infants which needed remission? Would not the grace of baptism, in this context, seem superfluous?
In essence, laying aside all the polemics and prejudices and academic intricacies, what Scriptural principle is being violated if a child is baptized and matures in his faith?

There is a good reason why these questions are hard to answer for those who exclusively advocate adult baptism: infant baptism is not an innovation, it is the practice of the Early Church.

Christ Reigns!!