After the Saviour's Ascension into the Heavens, the eleven Apostles and the rest of His disciples, the God-loving women who followed after Him from the beginning, His Mother, the most holy Virgin Mary, and His brethren-all together about 120 souls returned from the Mount of Olives to Jerusalem. Entering into the house where they gathered, they went into the upper room, and there they persevered in prayer and supplication, awaiting the coming of the Holy Spirit, as their Divine Teacher had promised them. In the meanwhile, they chose Matthias, who was elected to take the place of Judas among the Apostles.
All foods allowed during the week following Pentecost."
Apolytikion of the Feast of Pentecost in the Plagal of the Fourth Tone
Blessed are You, O Christ our God, who made fishermen all-wise, sending upon them the Holy Spirit and, through them, netting the world. O Loving One, glory to You.
When the Most High came down he confused the tongues, divided the nations; but when he parted the tongues of fire, he called all to unity, and with one voice we glorify the all-holy Spirit.
Give swift and stable comfort to your servants, Jesu, in the despondency of our spirits; do not part from our souls in troubles, do not be far from our minds in perils, but ever anticipate us. Be near us, be near you, who are everywhere; as you are also always with your Apostles, so unite yourself, O compassionate, with those who long for you, that united to you we may hymn and glorify your All-holy Spirit.