After the Lord's Ascension into heaven, the Apostles spent their days in prayer, preparing for the coming of the Holy Spirit. On the morning of the 50th day of His Resurrection, the Lord sent the Holy Spirit upon them as He had promised. There was the sound of a violent wind that filled the house, and tongues of fire appeared on each of the Apostles. They began to speak in various languages by the power of the Holy Spirit, and preached to those who were visiting in Jerusalem. Saint Peter revealed the meaning of the scriptures to the Jews, and his sermon is recorded in Acts chapter 2. Three thousand souls were baptized on that day.
In iconography, Saint Paul is present at the head of the Apostles, together with Saint Peter, despite the fact that he was not present and indeed was a persecutor of the Church at this time. Others who were present, such as the Virgin Mary, do not appear in the icon. Iconography is not merely a depiction of an event; it also reveals the event's spiritual reality. Pentecost was the divine ordination of the Apostles, who went into all the world to preach the Gospel and to ordain successors for themselves.