Baptism
Acts 16:15
And when she was baptized, and her household, she besought us, saying: If you have judged me to be faithful to the Lord, come into my house, and abide there.
Context of the passage
Lydia, a wealthy seller of purple in Philippi, becomes the first European convert, and her entire household is baptized with her.
Catholic reading
The baptism of an entire 'household' (oikos), a term in Greco-Roman usage that normally included young children and servants, reflects the apostolic practice of baptizing whole families, supporting the Catholic and ancient practice of infant baptism.
Common objection
'Household' likely refers only to servants and family members old enough to hear and believe the Gospel themselves, with no explicit mention of infants present.
Response
While Scripture doesn't specify ages, the consistent pattern of whole 'households' being baptized together without individual faith statements recorded for each member (also seen with the Philippian jailer, Acts 16:33), combined with unbroken patristic testimony to infant baptism, supports the practice's apostolic origin.