he drew his sword and was about to kill himself,
thinking that the prisoners had escaped.
But Paul shouted out in a loud voice,
"Do no harm to yourself; we are all here."
He asked for a light and rushed in and,
trembling with fear, he fell down before Paul and Silas.
Then he brought them out and said,
"Sirs, what must I do to be saved?"
And they said, "Believe in the Lord Jesus
and you and your household will be saved."
So they spoke the word of the Lord to him and to everyone in his house.
He took them in at that hour of the night and bathed their wounds;
then he and all his family were baptized at once.
He brought them up into his house and provided a meal
and with his household rejoiced at having come to faith in God.
1226 From the very day of Pentecost the Church has celebrated and administered holy Baptism. Indeed St. Peter declares to the crowd astounded by his preaching: "Repent, and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins; and you shall receive the gift of the Holy Spirit." The apostles and their collaborators offer Baptism to anyone who believed in Jesus: Jews, the God-fearing, pagans. Always, Baptism is seen as connected with faith: "Believe in the Lord Jesus, and you will be saved, you and your household," St. Paul declared to his jailer in Philippi. And the narrative continues, the jailer "was baptized at once, with all his family."
-- CCC 1226