I'm not sure how it happened, but the high sacramental theology of the reformers1 has been lost in most varieties of American protestantism (I can't really speak for the situation anywhere else in the world). Sacraments, as classically understood, are outward and visible signs of inward and spiritual grace. The more prevalent low view, on the contrary, understands the sacraments (sometimes referred to simply as "ordinances" to distance them from high sacramental theology, that of Roman Catholicism in particular) mostly as acts having personal significance, denying the presence of any special, objective grace given in the sacraments. So baptism is a public confession of faith in Christ rather than the sign and seal of the forgiveness of our sins and our reception into the covenant people of God. The Lord’s Supper, likewise, is a purely personal memorial, a time of devotional reflection on the death of Christ, in which Christ is not present in any special way.
The divide in sacramental theology is nowhere more evident than in the practice of infant baptism (paedobaptism). If the sacraments represent a personal confession of faith, then it follows as a matter of course that baptism should be withheld until the individual is old enough to make such a confession (believer’s baptism, or credobaptism). However, if the sacraments are God’s work rather than ours, this is far from obvious.
The theology of infant baptism I will be defending here follows closely Calvin's defense in book IV, chapter xvi of Institutes. This is the most convincing and thoroughly Biblical defense you are likely to find anywhere. If Calvin does not convince you, probably no one will. It is relatively short (about 35 pages), and well worth the read if you are interested. Another reason for following Calvin's exposition is that it represents the lowest common denominator among what I am calling classical protestants. The Lutheran doctrine of baptism is much higher than Calvin's, but I don't think a Lutheran would disagree with anything Calvin says about baptism - only claim that it was incomplete. And Anglicans, as usual, are vague enough to encompass a wide range of baptismal views.
Baptism is the sacrament of new life, by which one is welcomed into the covenant community of the people of God, and all the privileges associated therewith. As such, Baptism replaces and fulfills circumcision as the sign of the covenant between God and his people. As Christ's death fulfilled the Old Covenant sacrifices and the Lord's Supper fulfilled the Passover, so baptism fulfills the Old Covenant practice of circumcision. See Col. 2:11-12:
And in Him you were also circumcised with a circumcision made without hands, in the removal of the body of the flesh by the circumcision of Christ; having been buried with Him in baptism, in which you were also raised up with Him through faith in the working of God, who raised Him from the dead.Notice how Paul blends circumcision and baptism together. First of all, it is clear that both baptism and circumcision represent the same thing: death to the old life of sin, and rebirth into the new life of grace. Secondly, note the connecting word between verses 11 and 12: having. Our baptism is our circumcision. In other words, baptism has the same purpose for us that circumcision had for the Jews. It is the mark of membership in the new covenant, and the new life which that covenant represents. As circumcision (and, correspondingly, covenant membership) was extended by God's command both to adult converts and to babies born into the covenant, so the mark of the new covenant ought to be extended to babies as well as adult converts.
In affirmation of this, Jesus Himself rebuked his disciples for keeping the children (gr. paidon - according to Strong's, literally "infant" or, by extension, young boys/girls. See also the parallel account in Luke 18:15) from him: "But Jesus said, 'Let the children alone, and do not hinder them from coming to me, for the kingdom of heaven belongs to such as these.'" Jesus here affirms what credobaptism denies: the place of infants in the Kingdom of God. He does not say "Bring them to me a little later, after they have reached the Age of Accountability and are old enough to become members of the Kingdom of God." Just the opposite: He says "The Kingdom of God belongs to such as these." His aim is to prove that age is not a barrier to entrance in the kingdom. But if infants are rightly included as members of God's covenant people, why ought the sign of covenant membership be denied them? "The Kingdom of God belongs to such as these" is the central teaching of paedobaptism. The infant children of believing parents are to be treated as children of the covenant, not just the same as adults born outside the church, who have spent a lifetime in active rebellion against God.
St. Paul suggests something similar in I Cor. 7:14: "For the unbelieving husband is sanctified through his wife, and the unbelieving wife is sanctified through her believing husband; for otherwise your children are unclean, but now they are holy." This should be regarded as a reference to covenant promises extended to children by God because of a believing parent. In a framework where God's covenant extends only to those who are old enough to have faith in Him, this verse makes very little sense. It fits perfectly, however, into the covenantal framework associated with paedobaptism.
You are, perhaps, about to accuse me of wholesale rejection of the new covenant. Isn't it beyond dispute that the community of the new covenant is composed only of believers? Well, yes and no. The passage most often taken to infer this is Jer. 31:33-34:
"But this is the covenant which I will make with the house of Israel. After those days," declares the Lord, "I will put My law within them and on their heart I will write it; and I will be their God and they will be my people. They will not teach again, each man his neighbor and each man his brother, saying , 'Know the Lord', for they will all know Me, from the least of them to the greatest of them," declares the Lord, "for I will forgive their iniquity, and their sin I will remember no more."It's important to understand the telescopic character of Bible prophecy: many apparently straightforward Old Testament prophecies were/will be fulfilled in stages rather than all at once. The New Covenant as described in Jer. 31 has yet to come in its fullness. It is already, but not yet. It was inaugurated with Christ's coming, but it awaits its final fulfillment, when Christ will come on the clouds in glory and usher in the fullness of the kingdom. The law being written on the hearts of God's people is an obvious reference to the Holy Spirit's work begun at Pentecost, but we have yet to see the promise that "They will not teach again." Furthermore, the following verses (38-40) speak of the final rebuilding of Jerusalem, another yet-to-come event. The day will indeed come when everyone will know the Lord... but that day is not yet here.
But, one might ask, if infant baptism is a Biblical and Apostolic practice, why do al the instances of baptism in the New Testament refer to adults? First, it should be noted that the examples of baptisms in the NT are just as consistent with a classically protestant doctrine of baptism such as the one I am defending as they are with credobaptism. The presence of instances of adult converts being baptized proves only that adult converts should be baptized. Unfortunately, this is unhelpful. All Christians baptize adult converts! The debate is over covenant children. It is rather unrealistic to demand specific mention of an infant being baptized - that is just not the kind of detail the Biblical writers were interested in. About the only thing we might expect is exactly what we find: several passing references to the baptism of entire households (cf. I Cor. 1:16, Acts 16:15, 33). These passages are inconclusive because infants aren't mentioned explicitly, but I think they are suggestive. At the very least, they should establish that the Biblical examples do not clearly favor credobaptism over paedobaptism. To demand such an example is to presuppose that paedobaptism bears the burden of proof... but why ought this to be so? It might as well be demanded that credobaptists furnish an example of the child of a believer being denied baptism. But a hermeneutic like this is questionable anyway. One might use it to conclude all kinds of ridiculous things. Should communion not be given to women, because there are no Biblical examples of women partaking of it? This is absurd, of course, because our theology of the Lord's Supper informs us of who it ought to be given to, rather than the Biblical examples. The same should hold true for baptism. This essay is an attempt to build a Biblical theology of baptism in which infants are rightly included. Against such a theology, the absence of specific instances is no argument.
Probably the strongest argument against paedobaptism, though, involves the role of the baptized. Exactly what is it his/her responsibility to do/believe/understand? I know of no Biblical reasons to regard baptism as primarily or necessarily a public profession of faith (perhaps I've overlooked them?), so unless/until I could be shown that such a personal profession was integral to the Biblical practice of baptism, I'm disinclined to find it a compelling argument against paedobaptism that infants aren't capable of doing this. Nevertheless, baptism is a sign of repentance and faith. Since infants cannot posses either, shouldn't baptism be postponed until they can? This objection, however, applies with equal force to circumcision: for circumcision was also a sign of repentance and faith. See Romans 4:11a: "and he [Abraham] received the sign of circumcision, a seal of the righteousness of the faith which he had while uncircumcised". Paul calls Abraham's circumcision a seal of his faith (which is, coincidentally, precisely what baptism represents). A similar point is made in the previously quoted Col. 2:11, as well as various Old Testament passages (Deut. 10:16, 30:6; Jer. 4:4, 9:25) in which the Israelites are exhorted to circumcise their heart. What could these exhortations mean, except that the things signified by their physical circumcision (repentance and faith) were not present in them? Therefore, the question of why a sign of repentance should be given to infants ought to be addressed to God rather than paedobaptists. It should be enough to suggest, following Calvin, that "Infants are baptized into future repentance and faith, and even though these have not yet been formed in them, the seed of both lies hidden within them by the secret working of the Spirit."
Another argument against paedobaptism is that the practice of baptizing people before they make a decision to follow Christ creates the problem of producing a lot of baptized pagans, who reject Christ later in life. This objection is not very well thought-out, and I mention it only because I've heard it more than once. In the first place, I don't see why this is a problem. God's people can reject Him - most of the Jews did. If anything this increases their culpability, but there is certainly nothing fundamentally flawed with a practice which allows for the apostasy of God's people (as if it were possible to prevent apostasy). It becomes a problem only if you assume that God's covenant community is composed exclusively of believers - but this is exactly the point at issue! Secondly, the problem is not eliminated by credobaptism, for surely some people who have been baptized after making a public confession have later left the faith. The problem could only be eliminated by infallible knowledge of the eternal destiny of everyone whom one might baptize. And thirdly, it is simply false that paedobaptism results in more baptized unbelievers. Suppose those same children were baptized at 8 or 9 (a standard age for credobaptism, I think) instead of in infancy. Would there be fewer baptized unbelievers on this account? Only if the children renounced the faith of their parents before age 9! The chances of this happening are miniscule to nonexistent.
A further objection is that Biblical baptism was performed strictly by immersion. Since infant baptism is performed by either dipping the baby in water or poring water over his head, it is not Biblical baptism. This objection fails to be convincing because it is invariably (in my experience) put forward by those who a) replace wine with grape juice (and sometimes unleavened with leavened bread) in the Lord's Supper, and b) in all other things emphasize the spirit over the letter, the inner reality over the outward form. From people with beliefs such as these, this objection has more than a hint of intellectual dishonesty to it, as if those who use it are more concerned with defeating paedobaptism than with honest discourse. It is true that full immersion best represents the symbolism of baptism, and should always be performed when possible. Nevertheless, God is not so legalistic as to deny infants a share in his covenant because they cannot yet hold their breath.
I have tried to present a case for a classically Protestant doctrine of infant baptism, one that is faithful both to what the reformers themselves believed, and to the principles of the Reformation. Ultimately, the Bible is the only rule of faith and practice, and any doctrine not founded upon it cannot stand. I hope that, whether or not you are entirely convinced (though, of course, you ought to be :-), I have at least shown that infant baptism cannot be dismissed out of hand as so clearly opposed to scripture that no serious discussion of the issue is necessary. So far from being clearly un-Biblical, the doctrine has clear scriptural warrant.
1 It is a gross simplification, of course, to say that the reformers held to a high view of the sacraments. Zwingli and Meno Simons were both reformers with low theologies of the sacraments. Nevertheless, they stood outside the main thrusts of the classical reformation, as I am using the term (namely the Lutherans, the Reformed, and the church of England).