Baptism: For Believers AND Infants?

I know a lot of wonderful Baptist brothers and sisters in Christ and love them. If you are a Baptist, my reason for posting this is not to cause division. Rather, it is to hopefully help you understand why I (and others) believe what I do. And it'll help me to study the issue and perhaps remember scripture texts better.

Believer's baptism, in the sense that new believers are baptized, is clearly taught in scripture:

It is very clear that when someone becomes a Christian, they ought to be baptized:

“Go therefore and make disciples of all the nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit..." (Matthew 28:19)

"Then Crispus, the ruler of the synagogue, believed on the Lord with all his household. And many of the Corinthians, hearing, believed and were baptized." (Acts 18:8)

"Then Peter answered, “Can anyone forbid water, that these should not be baptized who have received the Holy Spirit just as we have?” And he commanded them to be baptized in the name of the Lord." (Acts 10:46b-48a)

"Now as they went down the road, they came to some water. And the eunuch said, “See, here is water. What hinders me from being baptized?” Then Philip said, “If you believe with all your heart, you may.” And he answered and said, “I believe that Jesus Christ is the Son of God.” So he commanded the chariot to stand still. And both Philip and the eunuch went down into the water, and he baptized him." (Acts 8:36-38)

Clearly, when an unbeliever first becomes a believer, he or she should be baptized. So what about children?

Circumcision related to baptism:

Colossians 2:11-12 shows that circumcision in the Old Testament and baptism in the New have the same spiritual significance:

"In whom also ye are circumcised with the circumcision made without hands, in putting off the body of the sins of the flesh by the circumcision of Christ: Buried with him in baptism, wherein also ye are risen with him through the faith of the operation of God, who hath raised him from the dead."

Just as baptism is something that believers do out of obedience to Christ, but not in order to be saved (Ephesians 2:8-9), so Romans 4:1-3 shows that Abraham, prior to being circumcised, believed God and it was counted to him for righteousness. First, God set up a covenant with Abraham (Gen 15) and afterwards instituted circumcision as a sign of the covenant.

Believer's and infant circumcision were both taught in scripture:

When God gave circumcision in Genesis 17, he commanded Abraham to circumcise those born in his household when they were eight days old.

However, someone in the Old Testament who joined God's covenant people as an adult would also be circumcised after believing. (Exodus 12:48).

So clearly, male children born in a covenant household were circumcised, as were new adult believing males. These don't preclude each other, but work in harmony. Of course, both those born on believers and those who professed faith as adults could either show themselves to be covenant keepers or covenant breakers in their futures.

Children of believers are covenant members, regarded as holy in some sense:

Note: I am not saying that children do not need to come to Christ to be saved. However, God has set up the family unit (e.g., as for me and my household, we will serve the Lord) and God looks on children of believers as holy (set apart) from the world in a covenantal sense:

1 Corinthians 7:14 shows that even children of one believer are regarded as holy: "For the unbelieving husband is sanctified by the wife, and the unbelieving wife is sanctified by the husband; otherwise your children would be unclean, but now they are holy."

"Then Peter said to them, “Repent, and let every one of you be baptized in the name of Jesus Christ for the remission of sins; and you shall receive the gift of the Holy Spirit. For the promise is to you and to your children, and to all who are afar off, as many as the Lord our God will call.”" (Acts 2:38-39)

Ephesians 6:1: "Children, obey your parents in the Lord, for this is right."

Psalm 8:2: "Out of the mouth of babes and nursing infants You have ordained strength, because of Your enemies, that You may silence the enemy and the avenger."

"Then they also brought infants to Him that He might touch them; but when the disciples saw it, they rebuked them. But Jesus called them to Him and said, “Let the little children come to Me, and do not forbid them; for of such is the kingdom of God." (Luke 18:15-16)

Here's a quote from Kevin DeYoung's article on infant baptism:

"Remarkably, though, this deeply spiritual sign was given to Ishmael as well as Isaac, even though only Isaac was the continuation of the promised line. The spiritual sign was not just for those who already embraced the spiritual reality. It was to be administered to Abraham and his sons. Circumcision was not a simple equation. It didn’t automatically mean the recipient of the sign was in possession of the thing signified. Circumcision, like baptism, also pointed to belonging, discipleship, covenant obligations, and allowed for future faith that would take hold of the realities symbolized. Just as there were some in Paul’s day who were circumcised but not really circumcised (Rom. 2:25-29), some children of Abraham who were not truly children of Abraham (Rom. 9:6-8), so in our day there are some who are baptized who are not truly baptized. Children should be marked as belonging to the covenant, but unless they exercise saving faith, they will not grab hold of the covenant blessings."

I could note that in the New Testament, multiple household baptisms took place. These don't specifically state whether there were infants/young children in these households but does show that God in His providence still often works with entire households.

Finally, in DeYoung's article, he claims that the early church practiced infant baptism within two centuries of Christ, and this wasn't questioned for over a thousand years. I don't know church history that well so cannot verify, but I'll take his claim on face value. Obviously, scripture is the final authority, but church history is helpful, and I do like his point: If infant baptism had been an abrupt change from the scriptures, why isn't there a record of earlier controversy about it?

As for the mode of baptism, I believe scripture teaches sprinkling is biblical (not that immersion doesn't count). Although I will not learn the subject as well by doing this, I will just link to an article by Greg Bahnsen on the subject of baptism and refer you to the section on the mode of it. By the way, he does a better and more comprehensive job than I do explaining baptism. (Although I do have a red flag when he says an unbelieving spouse ought to be baptized.)

So, what say you? In view of the scriptures above, why should infants not be baptized? I am open to scripture.

Edit: One other note: I suppose one result of not believing in infant baptism is that someone who had a mental disability and couldn't profess faith would never be able to be baptized.