The phrase used by Peter may be a baptismal formula that served to emphasize that no one can be kept from baptism if they belong to the church of Jesus Christ. Since the Gentile believers have come to faith in Christ and clearly received the Holy Spirit, they are most certainly members of his church and therefore there is nothing to stop them from receiving the sign of belonging, baptism
47 “Can anyone withhold water for baptizing these people, who have received the Holy Spirit just as we have?”