As I said, some denominations have no idea what the scriptural basis is for infant baptism. To be fair though even some denominations couldn't explain to you the scriptural justification for their doing it. They just do it because the church has been doing if for such a long, long time.
You were looking in the wrong places then and making the wrong assumptions, and perhaps also thinking like a gentile rather than a completed Jew entering the New Covenant from the Old Covenant, (which is actually all one covenant but 'better', more gracious, and with added promises and much wider application). WE, of Christ's church, are not 'gentiles' any longer, we have been grafted into the old olive tree root stock of the original 'church', the nation of faithful Israel.
There are two classes of people to whom baptism is applied, namely adults and infants
a.
Adult baptism: Baptism is intended for believers and their seed. In the words of the institution Jesus undoubtedly had in mind primarily the baptism of adults, for it was only with these that the disciples could begin in their missionary labours. His instruction implies that baptism had to be preceded by a profession of faith,
Mark.16:16. On the day of Pentecost those that received the word of Peter were baptized,
Acts.2:41; cf. also
Acts.8:37 (Auth. Ver.);
16:31-34. The Church should require a profession of faith from all adults seeking baptism. When such a profession is made, this is accepted by the Church at its face value, unless there are good reasons to doubt its sincerity.
b.
Infant Baptism: Baptists deny the right of infant baptism, since children cannot exercise faith, and since the New Testament contains no command to baptize children and does not record a single instance of such baptism. Yet this does not prove it un-biblical. Since the Jewish nation had previously understood infants to be included with their parents under The Old Covenant, it would be unreasonable to exclude them under the New, especially since the New is a 'Better Covenant' and 'More Gracious' than the old. Jews would have continued to believe their infants were covenant bound from birth and would have continued to circumcise 8 day old males even under the New Covenant. Circumcision was replaced by baptism, as scripture attests, yet there is not a single word of Apostolic disapproval anywhere in the New Testament against the baptizing of an infant. If it were frowned upon there should be objections in the NT, but there are none. There are examples of whole families being baptized though, and though infants are not specifically mentioned, it is unlikely that there were none or that Jews who entered the New Covenant would have allowed them to be excluded. There are also no recorded incidences of an adult or adolescent child of believing parents being baptized, anywhere in the new testament, yet we know that infant baptism was not only widely practiced in the church within150 to 200 years of the Apostolic church, and well before the closing of the canon of scripture, and there are no objections raised by any authority against its practice.
(1)
The scriptural basis for infant baptism: Infant baptism is not based on a single passage of scripture, but on a series of considerations. The covenant made with Abraham was primarily a spiritual covenant, though it also had a national aspect.
Rom.4:16-18; Gal.3:8, 9, 14. This covenant is still in force and is essentially the same as the "new covenant" of the present dispensation,
Rom.4:13-18; Gal.3:15-18; Heb.6:13-18. Children shared in the blessings of the covenant, received the sign of circumcision, and were reckoned as part of the congregation of Israel,
2 Chron.20:13; Joel.2:16. In the New Testament baptism is substituted for circumcision as the sign and seal of entrance into the covenant,
Acts.2:39; Col.2:11, 12. The "New Covenant" is represented in scripture as
more gracious than the old,
Isa.54:13; Jer.31:34; Heb.8:11, and therefore would hardly exclude children. This is also unlikely in view of such passages as
Matt.19:14; Acts.2:39; 1 Cor.7:14. Moreover, whole households were baptized and it is unlikely that these contained no children.
Acts.16:15; 16:33; 1 Cor.1:16.
(2)
The ground and operation of infant baptism. In reformed circles some hold that children are baptized on the ground of a presumptive regeneration, that is, on the assumption, (not the assurance), that they are regenerated. Others take the position that they are baptized on the ground of the all comprehensive covenant promise of God, which also includes the promise of regeneration, (immediately or in due course). This is my preferred view. The covenant promise affords the only certain and objective ground for the baptism of infants. But if the question is asked, how infant baptism can function as a means of grace to strengthen spiritual life, the answer is that it can at the very moment of its administration strengthen the regenerate life, if already present in the child, and can strengthen faith later on when the significance of baptism is more clearly understood. Its operation is not necessarily limited to the very moment of its administration.
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