Acts 2:1-47Pentecost is the Feast of Weeks celebrating the giving of the law on Mount Sinai when Israel was wondering in the wilderness. The disciples are gathered together, probably celebrating, when the Holy Spirit makes a dramatic entrance. They are celebrating the Word of God and now the Word is coming to dwell within them. The God who came in a pillar of fire, separated the Red Sea, and performed many miracles now placed His Spirit withing the believers. The same Spirit that gave Samson incredible strength, delivered David from danger so many times, and gave Solomon tremendous wisdom now resided within the people. The Spirit comes upon them with great noise and looked like fire resting upon them.
Peter makes us of this new gift and addresses the crowd. The first sermon of the early church is given. Peter; a fisherman with no education, who denied Jesus three times, and never really seemed to fully get it; stands up and begins preaching with great knowledge and power to the Bible, revealing Jesus from the Old Testament prophecies. The Spirit opened his mind to Jesus' teaching and gives him all the words to speak. Speaking while filled with the Spirit leads 3,000 people to Christ in the first ever sermon delivered.
With 3,000 new believers they now had to set up a way to disciple all of them and teach them what it means to follow Jesus as the Messiah. Many of these people had probably heard of Jesus for the first time ever. Thus the church was born. The church wasn't a building but a community of believers who would meet everyday in someones house and go through the Scriptures. They would still call themselves Jews, Jesus was just the fulfillment of Jewish teachings, and so they would still go to synagogue as well. The church was a community living life together.