The people had listened to Paul speaking up to this point [i.e., until he said the word “Gentiles”], then they raised their voices and shouted, “Do away with such a person from the earth; it is not right for him to live.”
This water prefigured immersion [into Christ], which now also saves you, not by removing dirt from the [physical] body, but [by serving] as an appeal [or, “pledge”] to God for a clear conscience through the raising of Jesus Christ from the dead.