Ultimately, Reformed evangelicals who affirm infant baptism do so because of their views of covenant continuity and the identity of God’s people. Those who baptize infants to mark them as covenant children believe in a continuity between God’s old covenant people and His new covenant people. Our Lord has one people, all of whom are saved by the work of Christ through their trust in God’s promises whether they live before or after our Savior’s ministry (Rom. 4:1–12; Gal. 3:15–29).
Therefore, the lack of an indisputable New Testament example of infant baptism is not strong evidence against the practice. (However, the households of Acts 16:11–15 and 1 Corinthians 1:16 likely included infants who would have been baptized when these households were baptized.) As the old covenant community included adult believers and their children, so does the new covenant community. If the old covenant sign of initiation (circumcision) identified covenant children, the new covenant sign of initiation (baptism) identifies covenant children today. In fact, the New Testament probably lacks an incontestable example of infant baptism because it was written mainly by ethnic Jews who trusted Christ. These writers knew that believers’ children are set apart unto the Lord. God had told them millennia earlier to mark their children as set apart through circumcision (Gen. 17), and they were accustomed to applying a visible sign of covenant membership to their children. They would have easily and rightly reasoned that baptism, which fulfills circumcision (Col. 2:11–13), is the new covenant way to keep God’s ancient command to mark covenant children.
Arguments over the covenant initiation sacrament in the first-century church were so heated that God had to reveal clearly that the sign had changed from circumcision to baptism (Acts 15; Gal. 3; Col. 2:11–13). Due to Genesis 17 and centuries of tradition, Jewish Christians would have needed an indisputable command from God to believe they should not apply the new sacrament of initiation to their children. Had God intended this momentous change, He almost certainly would have given such direction. This line of argument, when included with the other evidence we have discussed, leads us to conclude we should baptize the infant children of believers.
Those who do not baptize infants must view the new covenant community as one in which the children of believers take no real part before their conversion. This makes the new covenant community radically different from the old covenant community, and it also makes it hard to see how God can view the children of believers as set apart before their conversion (1 Cor. 7:14). Our views of the church and of baptism are intimately connected.