Pentecost means 'fiftieth'.
The feast of Pentecost is the New-Testament fulfilment of the Old-Testament feast of Weeks (Shavuot).
The feast of Weeks was a harvest festival, festival of the multiplication of the wheat; wheat-harvest. On this joyful day the Jews offered two loaves of bread to God in the temple in Jerusalem. The two loaves of ‘first-bread’ symbolised the total yield of wheat. You can see the loaves on the painting.
After Jesus died, His body was sown as a grain of wheat in the earth. His resurrection from the dead at Passover, is the beginning of a new life;
the grain of wheat producing many grains.
1 Korinthians 15 verse 20: But Christ has indeed been raised from the dead, the firstfruits of those who have fallen asleep.
The fulfilment with the Holy Spirit on the day of Pentecost is the culmination of the atonement work of Christ.
The resurrection proves His victory over death, and is the beginning of a new,
The outpouring of the Holy Spirit - expressed by the speaking in many different languages- is the sign of the beginning expansion of the Kingdom of God among all peoples.
The sign of fire signifies cleansing, purification of the believer.
The multiple tongues of fire signify the multiplicity of languages.
The sign of the wind signifies a speech driven by the breath (wind / ruach / spirit) of the Holy Spirit.
The group of disciples of Jesus that receives this sign will be multiplied and become a great multitude that no one can count; the full harvest, when He returns.
Revelation 7 verse 9.
Romans 8 verse 11:And if the Spirit of Him who raised Jesus from the dead is living in you, He who raised Christ from the dead will also give life to your mortal bodies because of His Spirit who lives in you.
Isaiah 57 verse 15 to 17.
Jeremiah 31 verse 33.
Ezekiel 36 verse 26 and 27.
Ezekiel 37 verse 9 and 10.
The indwelling of the Holy Spirit.
The Holy Spirit is the 'other advocate' who comes to dwell in the believers after Jesus' ascension, and will stay with them forever.
The believer is a temple of the Holy Spirit.
1 Corinthians 3 verse 16 and 17.
1 Corinthians 6 verse 19.
So is the community of the believers; the church.
The Holy Spirit brings Jesus' words to the believers' hearts.
John 14 verse 26.
He draws their attention to Jesus.
John 16 verse 14.
The believers will submit to the leadership and teachings of the Holy Spirit. He will guide them into all the truth.
John 16 verse 13.
The fire of God's love makes the believers speak the Word of God in the world.
The Holy Spirit, He will prove the world to be in the wrong about sin and righteousness and judgement.
John 16 verse 8.
The power of the Holy Spirit makes it possible for the believer to stand against sin, Satan and the world. He therefore must put on the full armor of God.
Ephesians 6 verse 10 to 20.
Hebrews 4 verse 12.
Fifty days after Passover the day of Pentecost comes to pass.