The first infusion of the Holy Spirit into the congregated disciples took place at "the third hour." Peter, on the day on which he experienced the vision of Universal Community, (exhibited) in that small vessel, had ascended into the more lofty parts of the house, for prayer's sake "at the sixth hour.
Further: since in the self-same commentary of Luke the third hour is demonstrated as an hour of prayer, about which hour it was that they who had received the initiatory gift of the Holy Spirit were held for drunkards; and the sixth, at which Peter went up on the roof; and the ninth, at which they entered the temple: why should we not understand that, with absolutely perfect indifference, we must pray always, and everywhere, and at every time; yet still that these three hours, as being more marked in things human-(hours) which divide the day, which distinguish businesses, which re-echo in the public ear-have likewise ever been of special solemnity in divine prayers? A persuasion which is sanctioned also by the corroborative fact of Daniel praying thrice in the day; of course, through exception of certain stated hours, no other, moreover, than the more marked and subsequently apostolic (hours)-the third, the sixth, the ninth.
When the blessed apostles
were gathered together
the place shook
and the scent of Paradise,
having recognized its home,
poured forth its perfumes,
delighting the heralds
by whom
the guests are instructed
and come to his banquet;
eagerly he awaits their arrival
for he is the Lover of mankind.
Dost thou perceive the type? What is this Pentecost? The time when the sickle was to be put to the harvest, and the ingathering was made. See now the reality, when the time was come to put in the sickle of the word: for here, as the sickle, keen-edged, came the Spirit down. For hear the words of Christ: "Lift up your eyes," He said, "and look on the fields, for they are white already to harvest." And again, "The harvest truly is great, but the laborers are few." But as the first-fruits of this harvest, He himself took our nature, and bore it up on high. Himself first put in the sickle. Therefore also He calls the Word the Seed. "When," it says, "the day of Pentecost was fully come": that is, when at the Pentecost, while about it, in short. For it was essential that the present events likewise should take place during the feast, that those who had witnessed the crucifixion of Christ, might also behold these.
Fifty days are reckoned from the celebration of the Passover (which, as Moses ordered, was accomplished by slaying the lamb, a type to signify the future passion of the Lord) to the day on which Moses received the law on tablets written by the finger of God. Likewise, when fifty days had passed from the slaying and resurrection of him who was led as a lamb to the slaughter, the finger of God, that is, the Holy Spirit filled the believers gathered in one place.
To the Hebrew people, now freed from Egypt, the law was given on Mount Sinai fifty days after the immolation of the paschal lamb. Similarly, after the passion of Christ in which the true Lamb of God was killed, just fifty days after his resurrection, the Holy Spirit fell upon the apostles and the whole group of believers. Thus the earnest Christian may easily perceive that the beginnings of the Old Covenant were at the service of the beginnings of the gospel and that the same Spirit who instituted the first established the Second Covenant.
"when the day of Pentecost was being fulfilled." That is, at Pentecost, about that feast itself, when the season of spiritual ripeness brings the sickle, when because of the feast many of those who had crucified him were present, and in order that they might receive the reproach for their own murder.
"When the days of the Pentecost were accomplished, they were all together in one place," etc. When fifty days had passed, as the Lord Christ had promised them, there was suddenly a mighty sound from heaven as the Holy Ghost came, and heavenly fire appeared above the heads of all who were sitting in the house, and they began to speak the tongues of various nations. As the news spread, men from various peoples who had gathered in Jerusalem came and wondered at them who, being Galileans, spoke of the wonderful works of God in the tongues of the peoples. Some, looking at the phenomenon reasonably, thought rightly that it had been granted by a gift of God; others, stupidly mocking, rather ascribed it to drunkenness.
And when the days of Pentecost were completed, they were all together in the same place. This is in the upper room, which they are said to have ascended. For whoever desires to be filled with the Holy Spirit must necessarily transcend the dwelling of the flesh through the contemplation of the mind. Just as the forty days during which the Lord conversed with His disciples after His resurrection signify the Church's journey in this world with the risen Christ, so the fiftieth day, on which the Holy Spirit is received, fittingly expresses the perfection of blessed rest, by which the labor of the temporal Church will be rewarded with eternal denarius. For the number forty itself, when computed by its equal parts, adds that denarius and makes fifty. The half of the number forty is twenty, a quarter is ten, a fifth is eight, an eighth is five, a tenth is four, a twentieth is two, a fortieth is one. Twenty, ten, eight, five, four, two, and one make fifty. The figure of this calculation is easily evident, because the present conflict generates for us the eternal joy of the jubilee, as the Apostle says: For our momentary and light affliction works for us an eternal weight of glory beyond all measure (II Cor. IV). Our true blessedness, however, is the eternal vision of the most high and blessed Trinity, wherein we glory in the immortality of both body and soul. For we consist of the four well-known qualities of the body. In the inner man, we are commanded to love God with all our heart, all our soul, and all our mind. And this is the perfect denarius of life, to rejoice in the present vision of divine glory. It is to be noted historically that among the ancients, the day of Pentecost, that is, the fiftieth day on which the law was given, was counted from the slaughter of the lamb. However, as the blessed Augustine explains, the fiftieth day here is counted not from the Lord's Passion, but from His resurrection, on which the Holy Spirit was sent. He, by the return of the old sign's example, most manifestly consecrated the Lord's day by His coming. At that same point in time, He showed that the true Pascha is to be celebrated on the Lord's day. For just as here, so also there God appeared in the vision of fire, as Exodus says: And Mount Sinai was altogether on a smoke because the Lord descended upon it in fire (Exod. XIX).
And when the days of Pentecost were completed, they were all together in the same place. Some Codices incorrectly have, Pentecosten. For Pentecoste in the nominative case means fiftieth; Pentecostes in the genitive, fiftieth's; Pentecosten in the accusative, fiftieth. However, no rule of speech allows us to say Pentecosten, when it should be said: When the fiftieth day was completed; or certainly as it is read in Greek in the singular number: And when the fiftieth day was completed. But truly in the prayers of the same day, it should be said: And celebrating the most sacred day of Pentecost, that is, the fiftieth. From the usage of this word, it is thought by some who do not know the Greek language that the solemnity of this day should also be called Pentecosten in the nominative case.
Why did this happen "when the day of Pentecost had come"? Because when the sickle was to come down upon the harvest, when it was time to gather the fruits, then the sickle of the word also had to come down; and as if in place of a sickle, the sharpened Holy Spirit descended.
And Christ says: "The harvest is plentiful, but the laborers are few" (Matt. 9:37), and in another place: "Look at the fields, how they are already white for harvest" (John 4:35). Having received the firstfruits, Christ Himself was the first to offer them up, and He Himself was the first to send the sickle. Why then did He send it "when the day of Pentecost had come"? Because this had to happen when the feast came again, so that those who had been present at the cross of Christ could see this as well.
The descent of the Holy Spirit took place on the day of Pentecost for the following reason. On the day of Pentecost in the Old Testament, the law was given. And so, on the same day that the law written on tablets was given, on that same day the legislation of the Holy Spirit was granted, inscribed not on tablets but on hearts. On the day of Pentecost the people of Israel received the law in the wilderness of Sinai, because on the fourteenth day of the first month by the lunar reckoning, when they celebrated the feast of unleavened bread and the mystery of Pascha, the sons of Israel went out of Egypt. From the fourteenth day count seventeen days to the end of the month, then thirty days of the following month and three days of the third. That is how many days Pentecost falls after the feast of unleavened bread or Pascha. Thus, from the fourteenth day of the first month to the third day of the third month is fifty days. Therefore it is said: "In the third month after the departure of the sons of Israel from the land of Egypt… the Lord said to Moses: Go to the people, [declare] and sanctify them today and tomorrow" (Exod. 19:1, 10). This the Lord says at the new moon. "On the third day," it continues, "the Lord will come down in the sight of all the people upon Mount Sinai" (v. 11). And so, on the same day that the law was given, it was fitting that the grace of the Spirit should also be granted, because just as the Savior, being about to undergo the holy passion, was pleased to surrender Himself to that passion not at any other time but at the time when the lamb was slain, so as to unite the truth with the very figure, so also the descent of the Holy Spirit, by the good pleasure from above, was granted not at any other time but at the time when the law was given, in order to show that both then and now the Holy Spirit is the Lawgiver. Thus, in the Old Testament the law was given on the fiftieth day. And after their arrival in the promised land, the Israelites established a feast in memory of this event, and at this time they offered to God from the firstfruits of the new harvest and from the new ears of grain; and this was a symbol of the feast. Since on the day of Pentecost they brought in sheaves of new fruits and various persons gathered under one sky, on this same day it was fitting that the firstfruits from every nation of all peoples living under heaven should be gathered into one sheaf of piety and, according to the apostolic word, be brought to God.
A sheaf of ears of grain served as a prototype of this, in order to prefigure the sheaves of souls chosen from different countries and brought to God.
In the church to which I belong this day is set apart for commemorating the descent of the Holy Ghost upon the first Christians shortly after the Ascension. I want to consider one of the phenomena which accompanied, or followed, this descent; the phenomenon which our translation calls "speaking with tongues" and which the learned call _glossolalia_. You will not suppose that I think this the most important aspect of Pentecost, but I have two reasons for selecting it. In the first place it would be ridiculous for me to speak about the nature of the Holy Ghost or the modes of His operation: that would be an attempt to teach where I have nearly all to learn. In the second place, _glossolalia_ has often been a stumbling-block to me. It is, to be frank, an embarrassing phenomenon.
[...] On the one hand, _glossolalia_ has remained an intermittent "variety of religious experience" down to the present day. Every now and then we hear that in some revivalist meeting one or more of those present has burst into a torrent of what appears to be gibberish. The thing does not seem to be edifying, and all non-Christian opinion would regard it as a kind of hysteria, an involuntary discharge of nervous excitement. A good deal even of Christian opinion would explain most instances of it in exactly the same way; and I must confess that it would be very hard to believe that in all instances of it the Holy Ghost is operating. We suspect, even if we cannot be sure, that it is usually an affair of the nerves. That is one horn of the dilemma. On the other hand, we cannot as Christians shelve the story of Pentecost or deny that there, at any rate, the speaking with tongues was miraculous. For the men spoke not gibberish but languages unknown to them though known to other people present. And the whole event of which this makes part is built into the very fabric of the birth-story of the Church. It is this very event which the risen Lord had told the Church to wait for—almost in the last words He uttered before His ascension. It looks, therefore, as if we shall have to say that the very same phenomenon which is sometimes not only natural but even pathological is at other times (or at least at one other time) the organ of the Holy Ghost.
[...] Those who spoke with tongues, as St. Paul did, can well understand how that holy phenomenon differed from the hysterical phenomenon—although be it remembered, they were in a sense exactly the same phenomenon, just as the very same sensation came to Pepys in love, in the enjoyment of music, and in sickness. Spiritual things are spiritually discerned. The spiritual man judges all things and is judged of none.
[AD 220] Tertullian on Acts 2:1