It was the Day of Pentecost, 50 days after the Passover. Pentecost, the Feast of Harvest or Weeks, is the second of three great Jewish festivals and is celebrated at the end of the barley harvest. This was a joyous time of giving great thanks to God and bringing to Him the first fruits of the harvest. According to Jewish Law, all adult Jewish men would come from wherever they were living to Jerusalem and personally be in attendance during this celebration.
In the early morning of that day, 120 of Jesus’ disciples were gathered together, waiting and praying. Suddenly a mighty wind came from heaven and filled the house they were in and what looked like tongues of fire rested on each disciple. And they were fully filled with the Holy Spirit and began speaking in other languages about the great things that God has done through the life, death, and resurrection of His Son Jesus.