The Day of Pentecost observes the event in which 120 believers waited together in the Upper Room and the Holy Spirit was poured out. The Day of Pentecost is described in some detail in Acts 2:1-4: "And when The Day of Pentecost has fully come, they were all with one accord in one place. And suddenly there came a sound from heaven, as of a rushing and mighty wind. Then there appeared to them divided tongues, as of fire, and one sat upon each of them. And they were all filled with the Holy Spirit and began to speak with other tongues."