Monday of the Holy Spirit
After the Ascension of Christ His disciples stayed in Jerusalem and in one room at the Zion frequently gathered and together they prayed the Lord awaiting impatiently the promised Comforter, The Holy Spirit, who proceeds from the Father. Matthias was voted in to replace Judas among the twelfe.
On the Descent of the Holy Spirit they all were together, when bluster of wind fulfilled the house and tongues of fire appeared and fall upon the apostles. When they came out on the roof of the house, they talked and preached to the gathered people in languages they had not known before, hence all gathered, even the Jews and persons of other faith could understand them. Three thousand people believed on this day the preaching of the apostles and then baptized. This day is considered as the day when the Church of Christ was born.