At Vespers on the day of Pentecost, we hear that the Holy Spirit is “the Fountain of goodness, through Whom the Father is known, and the Son is glorified.” He is “the living Fountain of spiritual gifts” Who “purifies us from our sins.” It is by the Holy Spirit that “the prophets, divine Apostles, and martyrs are crowned.” He is the source of life and of sanctification.
In the services of this day, we sing the same hymns as on Pentecost, except the Canon of the Holy Spirit, which is sung at Compline. The Vigil is not prescribed for the eve of today’s feast. We sing the Great Doxology at Matins, but not the Polyeleos. The Irmos of the Ninth Ode (“Hail, O Queen, glory of mothers and virgins…”) is sung in place of the Song of the Theotokos (“My soul magnifies the Lord…”).
At the Liturgy, the priest or deacon chants the Entrance Verse (“Be exalted in Thy strength, O Lord. We will sing and praise Thy power.”) as on the day of Pentecost. “Holy God” replaces “As many as have been baptized….” The dismissal of Pentecost is also used.
This whole week is fast-free, and the Leave-taking of Pentecost occurs on Saturday.
Tr by oca.org