The New Testament shows adults believing and being baptized, and it several times reports whole households being baptized without specifying who was in them. It never explicitly describes an infant baptism, and it never explicitly forbids one.
Two questions get tangled together: who is a proper subject of baptism, and what baptism actually accomplishes. A tradition's answer to the second usually drives its answer to the first.
Acts 2:38-39, Romans 6:3-4, Colossians 2:11-12
3Or don't you know that all of us who were baptized into Christ Jesus were baptized into his death? 4We were buried therefore with him through baptism into death, that just as Christ was raised from the dead through the glory of the Father, so we also might walk in newness of life. 5For if we have become united with him in the likeness of his death, we will also be part of his resurrection;
Every position here holds that baptism was commanded by Christ, that it is done in the name of the Father, Son, and Holy Spirit, that it marks entry into the visible church, and that faith is necessary for salvation. Most traditions recognize each other's baptisms even while disagreeing about practice.
Infant baptism, covenantal
Children of believers are baptized as members of the covenant community, as Israelite infants received the sign of the covenant, with faith expected to follow.
What it claims
The sign was applied to children under Abraham, and the new covenant is broader in mercy, not narrower. Peter's Pentecost promise is explicitly to you and to your children. Baptism is God's act of claiming and marking, not primarily the believer's testimony, so it can precede understanding as circumcision did.
Who holds it
and Reformed churches, most Anglicans, Lutherans, and Methodists. The Reformed version rests on covenant continuity; Lutheran and Anglican teaching adds a stronger sense of what baptism itself conveys.
The texts it stands on
Acts 2:39 For the promise is to you and to your children, and to all who are far off.
Colossians 2:11-12 Paul places baptism alongside a circumcision made without hands, which this view reads as a link between the two signs.
Acts 16:15, 33 Lydia and the jailer are baptized with their whole households.
Strongest case
It preserves the continuity of one covenant people across both testaments, and it puts the emphasis on God's initiative rather than on the strength or timing of a person's experience, which many find pastorally steadying.
Hardest question
Every baptism described in detail in the New Testament follows a personal response, and household need not include infants. Critics argue the covenant sign was always meant to shift with the new covenant's emphasis on personal faith.
Holding the map
Notice how much the practical disagreement narrows in real life. Traditions that baptize infants expect a personal profession later, in confirmation or its equivalent. Traditions that baptize believers still dedicate their children and raise them in the faith. The order differs more than the expectation.
This is also one of the places where a family may genuinely have to choose, since a congregation must practice one or the other. Knowing why the other side does what it does is the difference between a decision and a dismissal.
Questions that press on this one
None of these stands on its own. What you conclude here narrows what you can say there.
