Acts 16:33

And he took them the same hour of the night, and washed their stripes; and was baptized, he and all his, immediately.

This is another so-called "household" baptism; but no infants were mentioned; and the fact of Paul and Silas having spoken unto them the word of the Lord (Acts 16:32) proves that no infants are in view here.

The jailer did not merely "believe" in the Lord; he repented of his sins, as indicated by the washing of stripes he himself might have inflicted. That he was also baptized is clearly stated, not as something which he eventually did, but as being done "immediately," the same hour of the night. If there was any device by which the Holy Spirit might have revealed to men any more certainly that baptism was a requirement of this jailer to be met before he could be saved, this writer cannot imagine what it might have been.