Following the resurrection at Easter, Jesus appeared to his disciples in Jerusalem, specifically in the Upper Room. The disciples were initially startled, believing they saw a ghost, but Jesus reassured them by showing his hands and feet and eating with them.
He explained that his suffering and resurrection fulfilled the Scriptures and instructed them that repentance and forgiveness of sins would be preached in his name to all nations, beginning at Jerusalem. He urged them to remain in the city until they received “power from on high”, the Holy Spirit.
After these appearances, Jesus continued to teach the disciples for forty days. He then ascended to heaven in their presence, promising that they would soon be baptized with the Holy Spirit. The disciples returned to Jerusalem, where they chose Matthias to replace Judas Iscariot among the Twelve Apostles.
The pivotal moment for the early Christian church came at Pentecost. While the apostles and other followers were gathered, the Holy Spirit descended upon them with a sound like a violent wind and what appeared to be tongues of fire. All present were filled with the Holy Spirit and began speaking in different languages, enabling them to proclaim the message of Jesus to Jews from across the Roman world who were in Jerusalem for the festival. Peter addressed the crowd, explaining that this event fulfilled prophecy and calling them to repent and be baptized. About three thousand people responded.
The early followers, called “People of the Way,” quickly grew in Jerusalem, characterized by communal living, shared resources, and regular teaching by the apostles. Miraculous healings and bold preaching led to both admiration and opposition. The stoning of Stephen, the first Christian martyr, marked the start of active persecution. Many believers fled Jerusalem, spreading the message to Judea and Samaria.Among the persecutors was Saul of Tarsus, a zealous Pharisee. On his way to arrest Christians in Damascus, Saul experienced a dramatic encounter with the risen Christ. Blinded and confronted by Jesus, he was led into the city, where Ananias restored his sight. Saul was baptized and immediately began proclaiming Jesus as the Messiah, shocking those who knew of his former opposition. Paul (formerly Saul) became the most prominent missionary and theologian of the early church. He undertook several missionary journeys across Asia Minor, Greece, and beyond, founding Christian communities and writing letters that would become foundational to Christian doctrine. Paul’s efforts shifted the church’s focus from a primarily Jewish movement in Jerusalem to a global faith open to Gentiles. He emphasized the death and resurrection of Jesus as the basis for salvation and taught that faith in Christ was available to all, regardless of background.
The Christian church is traditionally understood to have been born on the day of Pentecost, 50 days after Jesus’ resurrection and ascension. This event is depicted in the New Testament, specifically in the Acts of the Apostles, where the Holy Spirit is said to have descended upon Jesus’ followers, empowering them to preach the Gospel and marking the beginning of the church’s mission.
By the end of the period covered in Acts, the Christian movement had established itself in major cities throughout the Roman Empire. It was in Antioch that followers of Jesus were first called “Christians.” The church’s inclusive message, communal support, and missionary zeal enabled it to grow rapidly despite opposition. Paul emerged as the chief defender and interpreter of Jesus’ message, shaping the identity and theology of the early Christian church.
The Acts of the Apostles thus records the transformation of a small group of frightened disciples, locked in a room after the crucifixion, into a dynamic, Spirit-filled movement, led by figures like Peter and ultimately Paul, that spread across the Roman world, to followers of Jesus today.
