In the Jewish calendar, the Feast of Weeks, or the Day of Pentecost, is fifty days after the Passover. It was on the Day of Pentecost after Jesus' death and resurrection when the Holy Spirit was poured out on Jesus' followers and the church began (Acts 2:1–47). Jesus had ascended to heaven ten days earlier, having been with His disciples for forty days following His resurrection. When Jesus ascended, He told His disciples, "But you will receive power when the Holy Spirit has come upon you, and you will be my witnesses in Jerusalem and in all Judea and Samaria, and to the end of the earth" (Acts 1:8). The Holy Spirit's coming is considered to be the start of the church.
When did the church begin? How did the church start?
The Greek word for "church," ekklesia, comes from two words meaning "called" and "out from and to." The church is essentially those who have been called out from the world for God. The Bible also talks about the church as the "body of Christ" (Ephesians 1:22–23; Colossians 1:18) as well as uses the imagery of marriage to describe Christ's relationship with the church (Ephesians 5:25–32; 2 Corinthians 11:2; Revelation 21). The church consists of those who have faith in the resurrection of Jesus and have been born again (Romans 10:9–10; John 3:3).
Jesus instituted the church in Matthew 16 when He told Peter "… Blessed are you, Simon Bar-Jonah! For flesh and blood has not revealed this to you, but my Father who is in heaven. And I tell you, you are Peter, and on this rock I will build my church, and the gates of hell shall not prevail against it" (Matthew 16:17–18). Roman Catholics believe "this rock" is a reference to Peter. Protestants believe the "rock" to be Jesus, and a reference to Peter's prior statement that Jesus is "the Christ, the Son of the living God" (Matthew 16:16).
In Acts 2 we read that the Holy Spirit comes in power upon the disciples and believers in Jerusalem as Jews from all over the region were visiting to celebrate the Feast of Weeks. There were about 120 followers of Christ there. "And suddenly there came from heaven a sound like a mighty rushing wind, and it filled the entire house where they were sitting. And divided tongues as of fire appeared to them and rested on each one of them. And they were all filled with the Holy Spirit and began to speak in other tongues as the Spirit gave them utterance" (Acts 2:1–4). Devout men from every nation were in Jerusalem and were amazed and perplexed that they could hear Jesus' followers speak in their native languages. Peter stood up and proclaimed the message of the gospel. The people were "cut to the heart" (Acts 2:37) and asked what to do. Peter told them to "Repent and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit. For the promise is for you and for your children and for all who are far off, everyone whom the Lord our God calls to himself" (Acts 2:38–39). About three thousand did (Acts 2:41)!
Jews began to worship Jesus, and news spread to others, including Samaritans and Gentiles (Acts 8—10). The church grew and became a threat to the religious and cultural power in Jerusalem. Paul, then called Saul, joined with some who persecuted Christians to even the point of death (Acts 7:58—8:3), before he encountered Jesus on his way to Damascus and believed (Acts 9).
That is the beginning of the church. More can be learned from reading Acts, which recounts the amazing spread of the church throughout the known world in about two generations.
What was God's purpose in establishing the church?
What is the definition of the church?
What is the universal church and how is it different from the local church?
What was the original church? Was the first church / original church the true church?
What should we look for in a church?
Truth about Church