In the traditions of the Orthodox Church there are many holidays. Trinity is one of the most important holidays after Easter and Christmas.
The essence of the feast of the Holy Trinity
On the day of the Holy Trinity, the church recalls a grand biblical event - the descent of the Holy Spirit on the apostles. This event laid the foundation of the Church of Christ. On this day, the approval of the Christian faith takes place throughout the world, which calls on its spiritual children to strengthen and renew the gifts of the Holy Spirit received during the Sacrament of Baptism. The mysterious Grace of God renews and transforms the inner spiritual world of every believing person, gives him the most pure, valuable and exalted. On the feast of the Holy Trinity, Orthodox Christians rejoice and celebrate the descent of the Holy Spirit on the apostles and the birth of the Church. Also on this day another hypostasis of God was revealed. In Old Testament times, people knew only about God, with the birth of Christ they saw His Only Begotten Son, and on the day of Pentecost people were able to learn about the Third Person of the Most Holy Trinity - the Holy Spirit.

Waiting for the Holy Spirit
The descent of the Holy Spirit on the Apostles on the day of Pentecost, as a grand turning point in world history, was told by the Evangelist Luke in the first chapters of the Acts of the Apostles. This event was not a surprise for those gathered - God predicted it through the mouths of the prophets, Jesus Christ explained the need for His crucifixion and comforted the grieving apostles, telling them about the coming of the Holy Spirit to complete the salvation of people. Waiting for the coming of the Holy Spirit? Virgin Mary, disciples of Christ, myrrh-bearing women and more than 100 people were in Jerusalem in the Zion chamber, in which the Last Supper with the Lord was held earlier. All gathered were waiting for the Promise of the Father promised by Jesus, although they did not know how and when it would happen. After the event that Jesus ascended into heaven, the tenth day came. The Jews celebrated on this day the feast of the Old Testament Pentecost - the deliverance of Jews from slavery in Egypt and the beginning of life in union with God. The descent of the Holy Spirit on the apostles did not happen on this day: it freed believers in Jesus Christ from devilish authority and was the basis for a new union with God in His Kingdom. It replaced the strict written laws of the Old Testament with the guidance of God in the spirit of love and freedom.

The Descent of the Holy Spirit on the Apostles
At nine in the morning, people who arrived in Jerusalem for the celebration of Pentecost gathered in temples for prayer and sacrifice. The descent of the Holy Spirit upon the apostles occurred suddenly: at first a noise arose over the Zionnice as from a stormy wind. The house with the holy apostles was filled with this noise, a lot of bright but not burning flames of fire appeared over their heads. Their spiritual properties were even more unusual: everyone on whom they descended felt an extraordinary burst of spiritual strength, inspiration and joy. Feeling peaceful, full of strength and love for God, the apostles began to express their joy with loud exclamations and the praise of God, discovering that they speak not only Hebrew, but also other languages unknown to them before. This happened the descent of the Holy Spirit on the apostles, who christened them fire, as predicted by the prophet John the Baptist.
The first sermon of Peter
The noise from the apostolic house attracted many people to it. The apostles with prayers and praises of God went to the roof of this house. Hearing these joyful prayers and singing, people were amazed that the disciples of Christ, mostly simple, uneducated people, speak different languages. And each of the people who came to the celebration in Jerusalem from different countries heard a native speech and understood what the apostles were talking about. In addition to the internal beneficial spiritual changes, the apostles were able, in different languages, without studying them, to successfully spread the gospel to different nations.
Seeing the bewilderment of those gathered around the house, the apostle Peter stepped forward and delivered his first brief sermon, in which he said that the ancient prediction of the miraculous descent of the Holy Spirit came true and that it was in him the salvation of people, that for this Jesus Christ suffered suffering on the cross. The sermon was simple, but spoken through the mouths of men by the Holy Spirit itself. These words penetrated the hearts of the people who were listening, and they immediately publicly repented of their sins and accepted Baptism. The church in one day increased from 120 people to three thousand. So the day of the descent of the Holy Spirit on the apostles was the beginning of the Church of Christ - a blessed society of believers who want to save their souls. According to the promise of the Lord, the Church will not be defeated by the enemies of faith until the end of the world.

Pentecost Worship
On the feast of the descent of the Holy Spirit on the apostles in the temples, one of the most colorful and beautiful services of the year is celebrated. The temples are decorated with summer greenery - parishioners come with wildflowers, twigs of birch. The floors of the temples are often sprinkled with freshly cut grass, whose inexpressible aroma, mixed with the smell of incense, creates an atmosphere of an extraordinary celebration. The colors of the servants' robes are matched to the decoration of the temple - also green colors.
After the Liturgy, churches often hold immediately a great supper. Despite the fact that the supper is usually served in the evening, an exception is made on this day due to the fact that many believers cannot attend it. Vespers chants glorify the Holy Spirit. While the service is in progress, the priest reads three special prayers: for the Church, for the salvation of all worshipers, for the repose of the souls of all the dead, even those in hell. All parishioners are on their knees at this time. Such a kneeling prayer ends the fifty-day period after Easter, during which earthly and kneeling bows were not made.

The Descent of the Holy Spirit on the Apostles. Iconography of the holiday
The composition and type of Pentecost iconography is one example of a change in the artistic form of an icon under the influence of Christian theology over the centuries. The separation of the celebration of Ascension and Pentecost began in the 4th century. Until that time, the celebration was one day, which was reflected in the icons of the Ascension-Pentecost. After the XV century, the celebration was divided, respectively, when there was a need for a separate display of Pentecost, the artists divided the icon into the upper part - “Ascension” - and the lower part - “Pentecost”. At the same time, the icon of Pentecost left the image of the Virgin, which was illogical. Therefore, in the East, the Virgin was not displayed on the icons, and Western artists continued to draw Her in the center of the Pentecostal icon. In the XVII century, Russian masters began to rely on Western models and again began to place the Virgin on the icons of the descent of the Holy Spirit.
Between the apostles, instead of the Theotokos, Etymasia is sometimes depicted - the Promised See, symbolizing God the Father, with the Gospel opened on it - the symbol of God the Son, and above them a soaring dove - the symbol of the Holy Spirit. Together, this means the symbol of the Trinity.
This “half-hearted” decision did not suit all artists; the search for a better form continued. The descent of the Holy Spirit had no analogues in history. To create a new iconographic composition, the scheme “Christ the Teacher among the Apostles” was taken as a basis. On this icon, Christ is located in the center, the apostles are standing on the sides. In the free space of the “arc” stands a table, a basket with scrolls. After some changes, metamorphoses led to that version of the icon, the form of which we know now.

Pentecost Icon
The earliest surviving image of the Descent of the Holy Spirit dates back to 586. This miniature of the Russian Gospel was created by the monk Rabul from Syria. The icon is also present in the Psalms and personal Gospels, in ancient manuscripts, on the frescoes of many ancient temples of Athos, Kiev, Novgorod and other churches. On the Sinai icons of the 7th-9th centuries, the apostles are depicted in a sitting position, and they receive the Holy Spirit in the form of rays of flame from the Savior, blessing them from heaven.
The icon “The Descent of the Holy Spirit upon the Apostles”, the photo of which is presented above, traditionally depicts the apostles in the Zion's chamber with fiery tongues above their heads. Seated in a semicircle of 12 disciples of Christ (instead of Judas Iscariot, the apostle Matthew, who was chosen to replace him , is depicted) are holding books and scrolls in their hands - symbols of church teaching. Their fingers are folded in gestures of blessing. Among the disciples of Christ who are on the icon, the apostle Paul is also depicted, who was not on that day in the Zion's chamber. This shows that the Holy Spirit descended not only on those who were in the upper room of Zion, but on the whole Church, which at that time consisted of twelve apostles. The empty space present on the icon between Paul and Peter shows the presence of the Holy Spirit at the head of the Church. From the XVII - XVII centuries on the icon the image of the Mother of God is approved. Although it is not mentioned in the Acts of the Apostles at this event, Luke writes that after the Ascension of Jesus Christ, all the apostles were in prayer with their wives and the Virgin. During one such meeting, the descent of the Holy Spirit upon the apostles occurred. Iconography approved a place for the Mother of God surrounded by apostles in the center of the icon.

Temples dedicated to the Holy Trinity
Although the relationship of the Holy Trinity in the Creed was finally formulated in the 4th century, the first churches in the name of the Holy Trinity did not appear in the Christian world until the 12th century. In Russia, the first temple of the Descent of the Holy Spirit on the Apostles was built in 1335 by the humble monk Sergius in the middle of the deaf Radonezh Bor. It became the basis of the Trinity-Sergius Lavra - one of the largest centers of spiritual life in Russia. Initially, a small wooden temple was built in the name of the Holy Trinity and several small cells. After the Church of the Descent of the Holy Spirit on the Apostles and the area around it became part of the monastery, and eventually the spiritual center of Moscow and nearby lands. Now, on the site of that temple, from 1423, a beautiful four-pillar cross-domed white-stone Trinity Cathedral rises around which the Lavra architectural ensemble has been formed for many centuries.