What does the Bible say about believers' baptism?

In Acts 16, we see the baptism of the Philippian jailer and his household, which supports the view of believers' baptism. Scripture emphasizes individual understanding and faith in the gospel before baptism, as seen in the actions of Paul and Silas. The jailer believed in God with all his household, indicating that those baptized were of an age to understand the gospel, thus reinforcing the idea that baptism is for believers only. This position is supported by the phrase 'they heard', which implies comprehension.