Jesus had laid the foundations of the Church during his apostolic life and communicated his powers to Her after His Resurrection. The Holy Ghost was to complete the formation of the Apostles and bestow upon them the power from on high.
The visible reign of Christ is followed by the visible reign of the Holy Ghost which is manifested by descending upon the disciples of Jesus. The feast of Pentecost is the feast of the promulgation of the Church.
For this reason, the basilica dedicated to St. Peter, head of the Church, was chosen for the Station on that day. Jesus, the Gospel tells us, had announced to his own people the coming of the divine Paraclete, and the Epistle shows us the fulfillment of this promise.
It is at the hour of Tierce that the Cenacle was invested by the Spirit of God. A stormy wind that suddenly blows around the house, and the appearance of tongues of fire inside, are the marvelous signs of this. Enlightened by the lights of the Holy Ghost and filled with the outpouring of His seven gifts, the Apostles are renewed and will in turn renew the whole universe.
And the High Mass, at the hour of Tierce, is the moment when we also receive "the Holy Ghost that Jesus, ascended into heaven, pours out on the children of adoption on this day", for each of the mysteries of the Cycle brings forth fruits of grace in our souls on the anniversary when the Church celebrates it.
We said during Advent to the Word: "Come, Lord, make atonement for the crimes of your people". This is the most beautiful and necessary of the ejaculatory prayers, for it is the Holy Ghost who, "gentle guest of our souls", is the principle of all our supernatural life.