I have given much more thought on this matter and listened to the debate between Sproul and MacArthur on Youtube and I find that baptist side more convincing. Theologically, what the paedobaptist side argues is that baptism is the new circumcision, being that the old testament foreshadows the new.
The problem with this line of reasoning is three fold:
1. If the connection between baptism being the necessary replacement for circumcision was so obvious, why is this rationale never explained in the New Testament, especially by Paul in Galatians?
Paul clearly interpreted circumcision as a work of the Law not to be practiced by Christians, like that of discerning between clean and unclean foods. If baptism was its replacement, he would have simply argued, “You foolish Galatians, why circumcise when you already have been baptized?” The fact he avoids this line of reasoning and uses Old Testament exegesis to speak of righteousness and covenants shows that paedobaptists are imposing a view on Scripture that is deliberately avoided in the New Testament.
2. Granted, there are plenty of OT Laws with NT applications, but this does not mean circumcision foreshadows baptism when it comes to the age of the one baptized.
The Law about unclean foods foreshadows the importance not only of what goes into our mouths, but what goes out of it. The Law about not using two different materials or not to cross-breed plants and animals foreshadows the importance of not marrying unbelievers. So yes, the Law about circumcision, in the way it sets apart a “peculiar people” does foreshadow baptism, which in many ways is the outward mark of the Christian. However, foreshadowing something obviously means a non-rigid understanding of the principle involved is necessary. I think it is a major leap that because baby males were circumcised on the eighth day, that babies need to be baptized on the eighth day, eighth month, first day, first second, or any time period.
3. The Old Testament foreshadows a time period more fitting for baptism, which is when the believer repents–this is supported by the witness of the New Testament.
The believer does not need to go far to find the best Old Testament foreshadowing of NT baptism. Simply look to the baptisms of John the Baptist! Men and women were practicing the OT rite of ritually cleansing, desiring “not the removal of dirt from the flesh, but an appeal to God for a good conscience” (1 Peter 3:21), in order to be clean before God before presenting a sacrifice in which to get atonement for sins. However, with baptism in the triune God, that atonement has been accomplished once and for all. For this reason, Paul describes us as being baptized into Christ’s death and resurrected in Him when we are taken out of the water. So, the best OT example of baptism, ritual cleansing, abides by the NT logic for baptism and maintains the important element of it being the desire of the believer’s heart. Paedobaptists are forced to argue that parents are making this pledge on behalf of their children, and as the basis for this use the flawed reasoning we already addressed in point number 2.
To wrap it up, the second and third century practice of baptism, even by Eusebius’ account, was already showing unbiblical understandings of grace. Eusebius records men withholding baptism to the point of death and rebaptizing beleivers because the person who baptized them turned out to be a heretic, as if the character of the baptizer holds sway over the one baptized. Obviously, baptism began to be coupled with confused notions of how grace is administered. The thing men started interpreting was that baptism in of itself was a means of salvation. No wonder, people wanted to baptize their babies. But, to baptize a baby thinking you are saving him is an unholy striving of the heart against God, for it is not the will of our hearts that saves but that of God’s.
It appears to me that infant baptism is a very old practice that originates not from apostolic practice, but rather a misunderstanding of what accords grace. The biblical reinterpretations used to justify the practice since then simply are highly speculative and ignore much simpler and clearer biblical understandings.