N the Old Testament, the feast of weeks (or Pentecost) fell 50 days after the feast of Passover. In the New Testament, Pentecost came 50 days after the resurrection of Christ (who was of course the ultimate Passover lamb). And, here in Acts 2 we find out why this feast took on a whole new meaning – or at least, a more complete meaning.
There were 120 devout believers (followers of Jesus Christ) gathered together waiting for the gift, which Christ had promised. They had been waiting for 10 days. They agreed; they were in harmony. And, God showed up. There was an audible effect: the sound of strong wind. There was a visual effect: fire above each believer. There was an internal effect: the believers were able to speak foreign languages that they had never learned. This last effect was clearly intended by God to initially attract the attention of the populous in Jerusalem. The disciples needed a platform to stand on for the gospel to be heard. Their unusual ability to speak any human language was enough for that (Acts 2:6).
There is no doubt that the unusual phenomena surrounding the baptism of the Holy Spirit must have given the disciples an extra spark of confidence in their mission of evangelization. But the real power was not in an experience, the real power was in the person of the Holy Spirit of Christ who now resided within each believer and who provided them with supernatural boldness to preach the gospel.