Postfeast of Pentecost — Day of the Holy Spirit
On the day after every Great Feast, the Orthodox Church honors the one through whom the Feast is made possible. On the day following the Nativity of the Lord, for example, we celebrate the Synaxis of the Most Holy Theotokos (December 26). On the day after Theophany, we commemorate Saint John the Baptist (January 7), and so on.
Today we honor the all-Holy, good, and life-creating Spirit, Who descended upon the Apostles at Pentecost in the form of fiery tongues in fulfillment of the Lord’s promise to send the Comforter to His disciples (JN 14:16). That same Holy Spirit remains within the Church throughout the ages, guiding it “into all truth”.
This whole week is fast-free, and the Leave-taking of Pentecost occurs on Saturday.