Day of Pentecost literally means “fiftieth day”; the word itself comes from the Greek language. Pentecost Sunday is celebrated annually by Christians across the world in memory of the day the Holy Spirit came upon the first century church. That day came fifty days after Jesus was crucified on Passover. (A pure lamb was sacrificed every Passover for centuries for the sins of Israel after the after were delivered from Egypt just as God directed them to. Two thousand years ago, on Passover, God sacrificed his own sinless Lamb for the redemption of the sin of the world.)
When Pentecost is mentioned, a couple of things can enter into a person’s mind. For the Jews, the time period Christians call “Pentecost” coincides with their Feast of Weeks. For a Christian, it brings to mind the events of the Upper Room in which the Holy Spirit anointed the disciples and apostles of Jesus Christ.
Just before he ascended to heaven after his resurrection, Jesus told his followers:
“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)”
In response to this promise, the disciples gathered in the upper room of a house and devoted themselves to prayer for days (v. 13-14). Until:
“When the day of Pentecost arrived, they were all together in one place. 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 (Act 2:1-4).”
This is the central event of Pentecost: the coming of the Holy Spirit in power. Before he ascended to heaven, Jesus breathed on the disciples and gave them the gift of the Spirit (John 20:22) but they were not filled with the power of the Spirit until the moment of Pentecost. Before this, throughout the Old Covenant, the Holy Spirit descended on men like Elijah, Elisha, Moses and even Saul (1 Sa 19:24), but it was only temporary.
Once his work was done in a person’s life – whether for a moment or years – the Holy Spirit departed from that person and returned to the Lord. On the day of Pentecost though, the Holy Spirit descended and stayed. He is actively in the world in the hearts of every believer today and will remain so until Christ returns at the rapture and the Holy Spirit once again returns to heaven with the Church (2 Thess 2:6). Only at that moment will his ministry on Earth be completed.