Jesus’ promise that Peter would be foundational in building the Church was fulfilled in three stages: Peter preached on the day of Pentecost (Acts 2). Then, he was present when the Samaritans received the Holy Spirit (Acts 8). Finally, he was summoned to the home of the Roman centurion Cornelius, who also believed and received the Holy Spirit (Acts 10). In this way, Peter “unlocked” three different worlds and opened the door of the Church to Jews, Samaritans, and Gentiles.