What does the Bible say about Infant Baptism? Should churches practice it?
The Bible does not explicitly mention infant baptism, but there are many things that the Bible does not mention that Christians rightly believe. Perhaps the most obvious of such doctrines are those regarding the Trinity (God exists in three persons and one essence) and the hypostatic union (Christ is one person with two natures, being fully human and fully divine). We believe that infant baptism is another such doctrine that the Bible does not state explicitly, but which the Bible assumes to be true and valid. This is not an easy doctrine to discover on one's own by even a thorough reading of the Bible, although it is a bit easier than the other doctrines I mentioned (on which it took the church hundreds of years to come to formal agreement).
The basic elements involved in the question of infant baptism related to who is in covenant with God, and what the sign of baptism means. It is our understanding that everyone who is part of the visible church is in covenant with God, and that baptism is the sign of the covenant which is to be applied to everyone who is in covenant with God.
This does not mean that everyone who is in covenant with God is saved. In fact, certainly many who are in covenant with God are not saved (like the Israelites who died in the wilderness after the exile, and Judas Escariot who betrayed Jesus). Those who are in covenant with God are in a special relationship with him, whereby he is extra patient and merciful to them. They have received promises from him that if they keep covenant, they will receive the blessings of the covenant, and if they break covenant they will fall under the covenant curses (Lev. 26). Only Jesus can keep covenant, so only those who are "in him," who have been united to him by faith in the gospel, are counted as covenant keepers and thereby receive the covenant blessings. Those who do not have faith cannot keep covenant and thereby fall under the covenant curses.
We believe that the Bible teaches that baptism is the New Testament sign of God's covenant with his people, just as circumcision was the sign of his covenant with his people in the Old Testament (Col. 2:11-12). Circumcision was to be applied to visible community of God's people in the Old Testament, without reference to their professed faith in God (Gen. 17:12-14). Because of the nature of circumcision, the sign was only administered to males, but the administration of the sign to the males constituted application of the sign to the entire community (Gen. 7:11). In the same way, baptism is to be applied to every member of the covenant community. Luke gives us some interesting insight into the minds of the early Christians when he writes about the baptism of Lydia's household in Acts 16:14-15. There he says that Lydia believed, and that her household was baptized. This does not mean that there were necessarily infants in Lydia's household. What is significant is that Luke mentions the baptism of the household without reference to the household's faith. That is, his assumption seems to have been that Lydia's faith was sufficient reason to justify baptizing everyone in her household, whether or not they also believed. Her belief, as head of her household, brought her entire household into covenant with God, and therefore it was appropriate to apply the sign of the covenant to the household. It is on this basis that we believe infants should be baptized.
For a more detailed explanation of our position, listen to our RealAudio lessons Infant Baptism (from our video) and Infant Baptism (from a Sunday School lesson). Both these lessons are by Dr. Richard L. Pratt, Jr.
Answer by Ra McLaughlin