SUNDAY, JUNE 23: The Godhead has been revealed and the mission of Jesus is fulfilled: In the Eastern Orthodox Christian Church, today is the feast of Pentecost. Fifty days following Great Pascha (Easter), Orthodox Christians recall the ancient day in Jerusalem when the Holy Spirit descended upon the disciples. As is written in the Acts of the Apostles, the disciples began speaking in languages they had not previously known; those nearby were awestruck when they overheard uneducated fishermen speaking God’s praises in alien tongues. (Learn more from OrthodoxWiki.) Eastern Christians believe the disciples were filled with the Holy Spirit, and thus the full Trinity had been revealed. For this reason, today’s feast is alternatively called Trinity Day.
In most Eastern Orthodox congregations, Pentecost services begin the evening prior to the feast. The Great Vespers of the evening give way to the Matins service of the day, and a special Kneeling Vespers is performed; although kneeling during Liturgy is suspended during the Paschal season, the suspension is lifted at Pentecost. (Get details from the Orthodox Church in America and the Greek Orthodox Archdiocese of America.) Liturgical readings and hymns will begin a “new year” of counting today, as each week they are read in terms of “weeks after Pentecost.”
In the Eastern Orthodox Church, the Monday after Pentecost is the Feast of the Holy Spirit; the Sunday following is the Feast of All Saints.