Since this thread is slowing down I will put my final post on the subject. This is a summary of the CredoBaptist position.
1. Christ established an order in the Great Commission. Go make disciples, baptize and teach. We see this order demonstrated throughout the New Testament as people come to faith (are made disciples), they are baptized and then continued to be taught by the Apostles/Leaders of the church. Therefore, baptism is for those who are "made disciples". Just as teaching is for those who are made disciples. If someone isn't a believer and sits under teaching it may lead them to faith, as the Holy Spirit uses the Teaching to give them understanding, but at the same time "The natural person does not accept the things of the Spirit of God, for they are folly to him," 1 Cor 2:14
2. Believers receive the Holy Spirit at belief. Gal 3:2 Eph 1:13. Apparently, this became the norm after Cornelius's Household came to faith. Before we see the Holy Spirit given in other ways. By Baptism and by the laying on of hands. But those baptized or had the laying on of hands were already believers. Nobody under the New Covenant where give the Holy Spirit except believers. The idea that the Holy Spirit is ever given apart from a personal conversion is foreign to the New Testament.
3. In the New Testament baptism is consistently shown as the final act of the conversion experience.
4. The only Biblical evidence given of the Bible indicating infant baptism was practiced is that some "households" were baptized. The idea of "households" containing infants goes beyond the text and requires an assumption that isn't in the text. We know that of all the "households" mentioned in the New Testament only one is ambiguous on if all the people in the household believed. For the others, it is clear that whoever was in the "household", they all believed.
5. Historical evidence of infant baptism outside of the Bible in the 1st Century doesn't exist. It isn't mentioned in the earliest non-scriptural documents. Perhaps the earliest documented evidence of church activity,
the Didache, instructs both those who are baptizing and those who are being baptized to fast one or two days. This seems to indicated that the person being baptized was old enough to fast without complications. I think we can all agree that it would be cruel and dangerous for a newborn baby to fast for "one or two days".
The only other, so called, first century evidence that infant baptism exist from the testimony of Polycarp, who indicated that the he been faithful for 86 years. This can be explained in a number of ways and is conjecture that Polycarp was indicating he was baptized as an infant.
6. The earliest historical evidence for infant baptism comes from late 2nd century and early 3rd century sources. This indicates that sometime between the end of the 1st century and the end of the 2nd century, some people started baptizing infants.
7. In the period between the 2nd Century and the 5th Century, there was a wide variety of practice in the church concerning baptism. Some waiting to be baptized due to an erroneous belief that their sins couldn't be forgiven after they were baptized (which is clearly an accretion that was eventually expelled from the church). Some were baptized as believers, even those from a Christian family. And some parents had their babies baptized as infants. Some waited until their children were three years old. It seems that there was wide latitude on the practice of baptism as there was little opposition to any of the forms mentioned.
8. The consensus among historians is that infant baptism became the norm around the 5th or 6th century. Mainly, due to the influence of Augustine and the rise of the Roman Catholic church.
With the lack of direct command to baptize infants in the New Testament, with lack of evidence that it was taught or performed by the Apostles or the first century church, and with the practice of baptism being so muddled in the following centuries, Credobaptist believe it is best to go to the order and pattern established in Scripture.
However, Credobaptist do not believe that the waters of baptism save. Baptism is a type or symbol of salvation. It outwardly expresses an inward "appeal to God".
Baptism, which corresponds to this, now saves you,
not as a removal of dirt from the body but as an appeal to God for a good conscience, through the resurrection of Jesus Christ,
Pastor John Piper puts it this way
Now the problem with this is that Peter seems very aware that his words are open to dangerous misuse. This is why, as soon as they are out of his mouth, as it were, he qualifies them lest we take them the wrong way. In verse 21 he does say, "Baptism now saves you" - that sounds like the water has a saving effect in and of itself apart from faith. He knows that is what it sounds like and so he adds immediately, "Not the removal of dirt from the flesh, but an appeal to God for a good conscience - through the resurrection of Jesus Christ." (Or your version might have: "the pledge of a good conscience toward God").
But the point seems to be this: When I speak of baptism saving, Peter says, I don't mean that the water, immersing the body and cleansing the flesh, is of any saving effect; what I mean is that, insofar as baptism is "an appeal to God for a good conscience," (or is "a pledge of a good conscience toward God"), it saves. Paul said in Romans 10:13, "Everyone who calls on the name of the Lord - everyone who appeals to the Lord - will be saved." Paul does not mean that faith alone fails to save. He means that faith calls on God. That's what faith does. Now Peter is saying, "Baptism is the God-ordained, symbolic expression of that call to God. It is an appeal to God - either in the form of repentance or in the form of commitment...
What is baptism? Baptism is a symbolic expression of the heart's "appeal to God." Baptism is a calling on God. It is a way of saying to God with our whole body, "I trust you to take me into Christ like Noah was taken into the ark, and to make Jesus the substitute for my sins and to bring me through these waters of death and judgment into new and everlasting life through the resurrection of Jesus my Lord."
This is what God is calling you to do. You do not save yourself. God saves you through the work of Christ. But you receive that salvation through calling on the name of the Lord, by trusting him. And it is God's will all over the world and in every culture - no matter how simple or how sophisticated - that this appeal to God be expressed in baptism. "Lord, I am entering the ark of Christ! Save me as I pass through the waters of death!" Amen.