Thank you Relative's Father for your question about infant Baptism. Because it is a big question I have moved it to a separate post, but if anyone is interested in the topic of Baptism see my original post on Baptism of December 27th. I again believe the Lutheran position on infant Baptism is the best position. I also support the Lutheran position on Infant Baptism for three reasons: It best accomplishes Jesus' Command in the Great Commission, it ties in well with the Old Testament use of Circumcision, and infant baptism is best supported by NT Scriptures, especially as shown in the Book of Acts. Let's Go!:
1). Jesus' Great Commission. In Matthew 28:19 Jesus commanded His Disciples to Go and make other Disciples and baptizing them in the name of the Triune God. And so, Christians have traditionally followed this instruction by having their children both instructed in God's Word and baptized as infants to comply with Jesus' Command.
The problem that is dealt with by infant Baptism is original sin. The Scriptures are clear that no one can enter the Kingdom of God without faith in Jesus Christ. And sprinkled through the Bible are examples of parents' faith acting on behalf of their children. See as examples, Genesis 9:9 and 17:10. And so, baptism may best be understood as the parents' faith in Jesus Christ being accounted to their young children until they reach an age of accountability. The Baptism is at least partly for the washing away of a person's sin (see Acts 22:16 and Titus 3:5).
2). Circumcision. There is a connection between the OT covenantal use of Circumcision of infants 8 days after they are born and the NT Church's use of Baptism. I do not know enough about this to write anything more, other than to make sure that it is raised.
3). Infant Baptism in the Book of Acts. But this is where the topic gets real fun to look at. There are a total of nine (9) baptisms of new converts described in the Book of Acts as a response to hearing the Gospel. In at least three (3) of these Baptisms described in Acts, the entire household of the New Christian is baptized along with them. Here is an example of this type of Household Baptism in the story of Lydia:
Acts 16:14-15 - One who heard us was a woman named Lydia, from the city of Thyatira, a seller of purple goods, who was a worshiper of God. The Lord opened her heart to pay attention to what was said by Paul. 15 And after she was baptized, and her household as well, she urged us, saying, "If you have judged me to be faithful to the Lord, come to my house and stay." And she prevailed upon us.
Here are the three main examples of families being baptized along with a New Christian:
Acts 16:15 Lydia of Thyatira, above;
Acts 16:33 Philippian Jailer;
Acts 18:8 Crispus, and as long as we are discussing family Baptisms, take a look at:
1 Cor. 1:16 Stephanus.
And so, infant Baptism started in the Church of Christ because of these descriptions of "household" baptisms shown in the Book of Acts.
And finally, let me add what Martin Luther said about infant Baptisms:
We do the same in infant Baptism. We bring the child with the purpose and hope that he may believe, and we pray God to grant him faith. But we do not baptize him on that account, but solely on the command of God…
Finally, we must know what Baptism signifies and why God ordained just this sign and external observance for the sacrament by which we are first received into the Christian church…These two parts, being dipped under the water and emerging from it, indicate the power and effect of Baptism, which is simply the slaying of the old Adam and the resurrection of the new man, both of which actions must continue in us our whole life long. Thus Christian life is nothing else than a daily Baptism, once begun and ever continued… (Luther's Large Catechism, Baptism, pp. 88-89).
So here is my quick summary on why infant Baptism makes sense and is properly a Biblical Sacrament. Baptism signifies the washing away of sins, it is Commanded by Jesus in His Great Commission and so should be obeyed by all Christians, and the early Church started the practice of baptizing those too young to have a saving faith as shown by the "household" baptisms performed in the Book of Acts. But most importantly, all Christians should be undergoing as Luther described a "daily Baptism", where we put to death our old Adam sinful nature with the resurrection of the new person we are in Christ.
I hope this helps - /s/Tom.