In almost every case in Scripture where you read of a household baptism, you are distinctly informed that they were also a believing household. In the case of Lydia it may not be so; but then there are remarkable circumstances about her case which render that information needless. In this instance they were all believers, and, therefore, they were all of them baptized. First, “HE” was baptised,—the jailor; he was ready first to submit himself to the ordinance in which he declared himself to be dead to the world, and risen anew in Christ Jesus. Then “all his” followed. What a glorious baptism, amidst the glare of the torches that night! perhaps in the prison hath, or in the impluvium which was usually in the center of most oriental houses, or perhaps the stream that watered Philippi ran by the prison wall, and was used for the occasion. It matters not, but into the water they descended, one after another, mother, children, servants; and Paul and Silas stood there delighted to aid them in declaring themselves to be on the Lord’s side, “buried with him in baptism.”

“Household Salvation,” MTP 17:1019 (1871)