Infant Baptism

Paul notes that baptism has replaced circumcision (Col. 2:11–12). In that passage, he refers to baptism as "the circumcision of Christ" and "the circumcision made without hands." Of course, usually only infants were circumcised under the Old Law; circumcision of adults was rare, since there were few converts to Judaism. If Paul meant to exclude infants, he would not have chosen circumcision as a parallel for baptism.
This comparison between who could receive baptism and circumcision is an appropriate one. In the Old Testament, if a man wanted to become a Jew, he had to believe in the God of Israel and be circumcised. In the New Testament, if one wants to become a Christian, one must believe in God and Jesus and be baptized. In the Old Testament, those born into Jewish households could be circumcised in anticipation of the Jewish faith in which they would be raised. Thus in the New Testament, those born in Christian households can be baptized in anticipation of the Christian faith in which they will be raised. The pattern is the same: If one is an adult, one must have faith before receiving the rite of membership; if one is a child too young to have faith, one may be given the rite of membership in the knowledge that one will be raised in the faith. This is the basis of Paul’s reference to baptism as "the circumcision of Christ"—that is, the Christian equivalent of circumcision.

To see the Catholic Argument for infant baptism click on title.