The feast of the Holy Trinity, also called the Pentecost, is dedicated to the descent of the Holy Spirit upon the apostles on the fiftieth day after Christ’s Resurrection. Through the descent of the Holy Spirit the Christian faith was established in the world and the Church of Christ began its existence. In the feast of the Pentecost the Church leads its faithful to the threshold of grace-filled life and summons them to renew and fortify within themselves the gifts of the Holy Spirit which they had received in the sacrament of baptism. It is impossible to lead a spiritual life without the grace of God. This mysterious force renews and transforms the entire inner world of a Christian. Everything that is most elevated and precious, which anyone may wish for himself – is given to us by the Holy Spirit. This is why the feast of the Holy Trinity is celebrated so joyously and triumphantly by Orthodox Christians.

God revealed Himself to people gradually: in Old Testament times people knew only God the Father; from the time of Christ’s nativity they came to know His Only-begotten Son; and on the day of the descent of the Holy Spirit people learned of the third Person of the Holy Trinity, and thus they learned to believe in and glorify God, one in essence and triune in Persons – the Father, the Son and the Holy Spirit – the indivisible Trinity.

The descent of the Holy Spirit upon the apostles on the day of the Pentecost is described by the Evangelist Luke in the opening chapters of his book of the “Acts of the Apostles.” God decided to make this event a turning point in world history.

The Pentecost – i.e. the 50th day after the feast of Passover – was one of the three major Old Testament feasts. This feast celebrated the acceptance of the ten commandments brought down by the Prophet Moses from Mount Sinai, when 1,500 years before the birth of Christ, at the foot of Mount Sinai, the Jewish people, just freed from bondage in Egypt, entered into a covenant with God. The Jews promised God their obedience, while the Lord promised them His favor. The feast of the Pentecost usually coincided with the end of harvest time and was thus celebrated especially joyously. Many Jews, dispersed throughout the various countries of the widespread Roman Empire, tried to come to Jerusalem for this holiday. Having been born in other countries, many of them had difficulty understanding their native Jewish tongue; however, they tried to observe their national and religious customs and from time to time make a pilgrimage to Jerusalem.

The descent of the Holy Spirit was not an unexpected event for the apostles. Several centuries before the birth of the Saviour, the Lord God already began to prepare the people for the day of their spiritual rebirth, and foretold through the prophets: “And it shall come to pass afterward, that I will pour out my spirit upon all flesh… For I will pour water upon him that is thirsty, and floods upon dry ground … Therefore with joy shall ye draw water out of the wells of salvation… A new heart also will I give you, and a new spirit will I put within you, and I will take away the stony heart out of your flesh, and I will give you a heart of flesh. And I will put My spirit within you, and cause you to walk in My statutes, and ye shall keep My judgments, and do them.”

Preparing to return to His Heavenly Father, our Lord Jesus Christ, on the eve of His crucifixion, dedicates his farewell talk with the apostles to the forthcoming descent of the Holy Spirit. The Lord explains to the disciples that the Comforter – the Holy Spirit – is soon due to come down, in order to finish the accomplishment of the salvation of mankind. “And I will pray the Father, – the Lord says to the apostles, – and He shall give you another Comforter, that He may abide with you forever, – the Spirit of Truth… He shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you… He, the Spirit of Truth, Who proceedeth from the Father, He shall testify of Me.”

Preparing to accept the Holy Spirit after the Lord’s ascension to heaven, Christ’s disciples, together with the Holy Virgin Mary, several myrrh-bearing women and other believers (approximately 120 people in all), were in Jerusalem for the Pentecost, waiting in the so-called “Zion chamber.” This was probably the same large room in which took place the Mystic Supper prior to the Lord’s suffering. The apostles and all the others were waiting for the Saviour to send them the promised Comforter, at which time they would become filled with power from above, although they did not know the exact manner of the Holy Spirit’s coming. Since the Lord Jesus Christ had died and had arisen during the course of the Old Testament Passover, the feast of the Pentecost in that year fell on the 50th day of His resurrection.

And so, in the ninth hour of the morning, when the people usually gathered in the temple for sacrifice and prayer, a noise as of a tempest was suddenly heard over the Zion chamber. This noise filled the house in which the apostles were gathered, and at the same time a multitude of fiery tongues appeared over the apostles’ heads and began to descend upon each one of them. These tongues of flame possessed an extraordinary characteristic: they shone, but did not burn. But even more extraordinary were the spiritual qualities which these mysterious tongues of flame endowed. Each person upon whom such a flame descended experienced an onrush of spiritual strength and, simultaneously, indescribable joy and ardor. Each began to feel himself a totally different person: at peace, full of life and fervent love for God. The apostles began to express these inner changes and novel feelings in joyous exclamations and a loud glorification of God. And at this point it was discovered that they were speaking not in their native Jewish tongue, but in other languages that were unknown to them. In this manner the apostles were baptized with the Holy Spirit and fire, as had been prophesied by St. John the Baptist.

Meanwhile, the noise which sounded like a tempest attracted many people to the apostles’ house. Seeing all the people gathering together from everywhere, the apostles went outside with prayers of laudation and glorification of God. Hearing this stream of joyous prayer, the people who had gathered around the house were struck by an inexplicable event: Christ’s disciples, for the most part men of Galilee, all seemingly illiterate, from whom it was impossible to expect knowledge of any other tongue except their native one, suddenly began to speak in different foreign languages, so that no matter how varied was the crowd of people who had come to Jerusalem from different countries, each one heard his own native tongue. But among the crowd there were also cynics who were not ashamed to laugh at the inspired preachers, saying that the apostles had obviously drunk wine at such an early hour. In reality, the power of the Holy Spirit was made manifest at that time not only in various blessed internal changes, but also in the external gift of tongues for the express reason of allowing the apostles to spread the Gospel among different nations more successfully, without having the need to study foreign languages.

Seeing the people’s bewilderment, Apostle Peter stepped forward and preached his first sermon, in which he explained to all those who had gathered there that the descent of the Holy Spirit fulfilled the ancient prophecy of Joel, who had said in the name of God: “And it shall come to pass afterward, that I will pour out My spirit upon all flesh; and your sons and your daughters shall prophesy, your old men shall dream dreams, your young men shall see visions. And also upon the servants and upon the handmaidens in those days will I pour out My spirit; and I will show wonders in the heavens and in the earth.” The apostle explained that precisely in this kind of descent of the Holy Spirit was the salvation of mankind to be achieved, and in order to make mankind worthy of the grace of the Holy Spirit, the Messiah – our Lord Jesus Christ – suffered death on the cross and arose from the dead.

This sermon was short and simple, but since it was the Holy Spirit speaking through Peter’s lips, these words penetrated into the hearts of the listeners. Many of them were deeply moved and asked him: “What should we do?” – “Repent, – Apostle Peter replied to them, – and let each one of you be baptized in the name of Jesus Christ.” And not only will you be forgiven, but you will receive the grace of the Holy Spirit yourselves.

Many of those who came to believe in Christ through Apostle Peter’s words publicly repented of their sins on-the-spot, were baptized, and by the evening of that day the Church of Christ grew from 120 to 3,000 people. With this miraculous event began the existence of the Church of Christ – the grace-filled community of believers in which all are summoned to save their souls. The Lord promised that the Church will remain unvanquished by the forces of hell to the very end of the world’s existence!

It should be noted that the coincidence of two remarkable events – the descent of the Holy Spirit and the Jewish Pentecost – falling on the same day was not random. The Old Testament Pentecost celebrated the deliverance of the Jews from Egyptian bondage and the beginning of a life of freedom in an alliance with God. The descent of the Holy Spirit upon believers in Jesus Christ achieved the deliverance of these believers from the power of the devil, and was the beginning of a new, grace-filled alliance with God in His spiritual Kingdom. Thus the feast of the Pentecost became the day when the Old Testament theocracy, which had begun with Sinai and had for a long time ruled society through a harsh written law, was replaced by a New Testament rule, in which believers are ruled by God Himself in a spirit of freedom and love.

Having deeply experienced the events of the Lord’s suffering, death and resurrection, the holy apostles had matured by the time of the Pentecost and had become ripe for being endowed with the gifts of the Holy Spirit. It was then that the fullness of God’s grace descended upon them, and they were the first to taste of the spiritual fruits of the Son of God’s salvific labors on our behalf.