Infant Baptism, Infant Faith, and Infant Confession through Godparents
Some people say that infants should not be baptized. But the Bible teaches otherwise. In 1 Co 10, Paul notes that everyone in Israel — infants as well as adults — were “all” under the cloud and that “all” passed through the Red sea, and that “all” were “baptized into Moses in the cloud and in the sea” (vv. 1-2). Paul then twice writes that this event serves as an example that the Christian church needs to follow and learn (1 Co 10.6, 11).
It is worth emphasizing that Paul points to Israel's baptism as a nation in the Red Sea. And Paul expressly says that Israel's baptism in the Red Sea serves as an example for the Christian church to follow. So when we then think biblically about the Great Commission that Jesus gave us -- that we are to make disciples of the nations by baptizing them i.e., by baptizing the nations -- then we cannot help but draw upon the single example of a national baptism that God gives us in the Scriptures, and that is Israel's national baptism, which included the baptism of "all" who were in Israel, including the little babies.
So, too, Peter says “Repent and be baptized, everyone of you, in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit” (Acts 2.38). Peter then expressly states that this promise is for the children of his hearers, as well as for Gentiles who are far off.
In response, people who say that infants should not be baptized say that Peter’s promise does not apply to babies, because babies cannot repent.
But let’s consider what the Bible actually teaches that babies can do: Infants can praise God (Ps 8.2) and can be filled with the Spirit (Lk 1.15). So, too, the Scriptures teach us that infants can fall down and worship God (2 Chronicles 20.13 with 18). Similarly, “little ones” (which is the Hebrew word translated as “children” by the NIV), “stand in the presence of God” (Dt 29.10-11), and enter into a covenant with God which “confirms you this day as his people, that he may be your God” (Dt 29.13).
So when talking about whether babies can have faith, what do we believe? God's word or human eyes?
To be sure, infants cannot do all those things by themselves. That's why we have their parents and godparents speak for them before God. The Bible teaches this as well. The Bible teaches that representatives can speak for and represent those who can't. The “whole congregation of the Lord,” which includes infants, is said to “speak” through only a few representatives (Josh 22.14-16). And “all” are said to “hear” when only the representatives hear (Josh 23.2, cf., 24.1-2). So, too, “all” are committed when representatives gather before God (2 Chr 5.2-3, cf., chs 5-7, esp., 6.3, 7.4). The Bible’s representative principle extends to generational representation as well (Dt 29.14-15). So, too, in baptism, adults speak for and represent the infant. Godparents speaking for infants is Biblical. And, thus, the Apostolic practice of baptizing "households" (Acts 16.15, 33, 18.8, 1 Co 1.16) is entirely nonproblematic for Lutherans.
The Bible makes clear that baptism is for “all,” and that the forgiveness promised in baptism is explicitly also “for our children.” The Scriptures teach us that infants can do all things that believers do – stand before God, fall down and worship God, praise God, and be members of God’s people. Just as representatives in the Bible speak for the whole assembly of God—including infants—parents and godparents can speak for their children, expressing their faith and their repentance. The form of baptism used in Lutheran churches is entirely consistent with what the Bible teaches us about God’s relationship with the infants of believing parents. All of us are saved by baptism into Jesus Christ, adult and child alike.
Finally, as for the thief on the cross. God blessed him, but it's simply and obviously wrong to draw conclusions contrary to the Scriptures from exceptional circumstances. Jesus gives us the general practice: He tells his church to make disciples by baptizing them and teaching them his word. You thereby nullify the Word of God by trying to make a rule out of an exception.