Pentecost is the celebration of the person of the Holy Spirit coming upon the Apostles
On the day of Pentecost when the seven weeks of Easter had come to an end, Christ’s Passover is fulfilled in the outpouring of the Holy Spirit, manifested, given, and communicated as a divine person: of his fullness, Christ, the Lord, pours out the Spirit in abundance. (Ac 2:36)
On that day, the Holy Trinity is fully revealed. Since that day, the Kingdom announced by Christ has been open to those who believe in him: in the humility of the flesh and in faith, they already share in the communion of the Holy Trinity. By his coming, which never ceases, the Holy Spirit causes the world to enter into the “last days,” the time of the Church, the Kingdom already inherited though not yet consummated.
We have seen the true Light, we have received the heavenly Spirit, we have found the true faith: we adore the indivisible Trinity, who has saved us. (Byzantine liturgy, Pentecost Vespers, Troparion, repeated after communion)
The Holy Spirit – God’s gift
“God is Love” (Jn 4:8.16) and love is his first gift, containing all others. “God’s love has been poured into our hearts through the Holy Spirit who has been given to us.” (Rm 5:5) Because we are dead or at least wounded through sin, the first effect of the gift of love is the forgiveness of our sins. The communion of the Holy Spirit (2 Co 13:13) in the Church restores to the baptized the divine likeness lost through sin.
He, then, gives us the “pledge” or “first fruits” of our inheritance: the very life of the Holy Trinity, which is to love as “God (has) loved us.” This love (the “charity” of 1 Co 13) is the source of the new life in Christ, made possible because we have received “power” from the Holy Spirit. (Ac 1:8) By this power of the Spirit, God’s children can bear much fruit. He who has grafted us onto the true vine will make us bear “the fruit of the Spirit: . . . love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control.”129 “We live by the Spirit”; the more we renounce ourselves, the more we “walk by the Spirit.” (Ga 5:25)
Through the Holy Spirit we are restored to paradise, led back to the Kingdom of heaven, and adopted as children, given confidence to call God “Father” and to share in Christ’s grace, called children of light and given a share in eternal glory. (St. Basil, De Spiritu Sancto, 15,36)
What happens at Pentecost?
In the Christian tradition, Pentecost is the celebration of the person of the Holy Spirit coming upon the Apostles, Mary, and the first followers of Jesus, who were gathered together in the Upper Room.
A “strong, driving” wind filled the room where they were gathered, and tongues of fire came to rest on their heads, allowing them to speak in different languages so that they could understand each other. It was such a strange phenomenon that some people thought the Christians were just drunk – but Peter pointed out that it was only the morning, and that the phenomenon was caused by the Holy Spirit.
The Holy Spirit also gave the apostles the other gifts and fruits necessary to fulfill the great commission – to go out and preach the Gospel to all nations. It fulfills the New Testament promise from Christ (Luke 24:46-49) that the Apostles would be “clothed with power” before they would be sent out to spread the Gospel.
Where’s that in the bible?
The main event of Pentecost (the strong driving wind and tongues of fire) takes place in Acts 2:13, though the events immediately following (Peter’s homily, the baptism of thousands) continue through verse 41.
Happy Birthday, Church
It was right after Pentecost that Peter, inspired by the Holy Spirit, preached his first homily to Jews and other non-believers, in which he opened the scriptures of the Old Testament, showing how the prophet Joel prophesied events and the coming of the Holy Spirit at Pentecost.
He also told the people that the Jesus they crucified is the Lord and was raised from the dead, which “cut them to the heart.” When they asked what they should do, Peter exhorted them to repent of their sins and to be baptised. According to the account in Acts, about 3,000 people were baptised following Peter’s sermon.
For this reason, Pentecost is considered the birthday of the Church – Peter, the first Pope, preaches for the first time and converts thousands of new believers. The apostles and believers, for the first time, were united by a common language, and a common zeal and purpose to go and preach the Gospel.