Translated by Ch. Browne and J. Swallow.
I. Let us reason a little about the Festival, that we may keep it spiritually. For different persons have different ways of keeping Festival; but to the worshipper of the Word a discourse seems best; and of discourses, that which is best adapted to the occasion. And of all beautiful things none gives so much joy to the lover of the beautiful, as that the lover of festivals should keep them spiritually. Let us look into the matter thus. The Jew keeps festival as well as we, but only in the letter. For while following after the bodily Law, he has not attained to the spiritual Law. The Greek too keeps festival, but only in the body, and in honour of his own gods and demons, some of whom are creators of passion by their own admission, and others were honoured out of passion. Therefore even their manner of keeping festival is passionate, as though their very sin were an honour to God, in Whom their passion takes refuge as a thing to be proud of.  We too keep festival, but we keep it as is pleasing to the Spirit. And it is pleasing to Him that we should keep it by discharging some duty, either of action or speech. This then is our manner of keeping festival, to treasure up in our soul some of those things which are permanent and will cleave to it, not of those which will forsake us and be destroyed, and which only tickle our senses for a little while; whereas they are for the most part, in my judgment at least, harmful and ruinous. For sufficient unto the body is the evil thereof. What need has that fire of further fuel, or that beast of more plentiful food, to make it more uncontrollable, and too violent for reason?
II. Wherefore we must keep the feast spiritually. And this is the beginning of our discourse; for we must speak, even if our speech do seem a little too discursive; and we must be diligent for the sake of those who love learning, that we may as it were mix up some seasoning with our solemn festival. The children of the Hebrews do honour to the number Seven, according to the legislation of Moses (as did the Pythagoreans in later days to the number Four, by which indeed they were in the habit of swearing  as the Simonians and Marcionites  do by the number Eight and the number Thirty, inasmuch as they have given names to and reverence a system of AEons of these numbers); I cannot say by what rules of analogy, or in consequence of what power of this number; anyhow they do honour to it. One thing indeed is evident, that God, having in six days created matter, and given it form, and having arranged it in all kinds of shapes and mixtures, and having made this present visible world, on the seventh day rested from all His works, as is shewn by the very name of the Sabbath, which in Hebrew means Rest. If there be, however, any more lofty reason than this, let others discuss it. But this honour which they pay to it is not confined to days alone, but also extends to years. That belonging to days the Sabbath proves, because it is continually observed among them; and in accordance with this the removal of leaven is for that number of days.  And that belonging to years is shewn by the seventh year, the year of Release;  and it consists not only of Hebdomads, but of Hebdomads of Hebdomads, alike in days and years. The Hebdomads of days give birth to Pentecost, a day called holy among them; and those of years to what they call the Jubilee, which also has a release of land, and a manumission of slaves, and a release of possessions bought. For this nation consecrates to God, not only the firstfruits of offspring, or of firstborn, but also those of days and years. Thus the veneration paid to the number Seven gave rise also to the veneration of Pentecost. For seven being multiplied by seven generates fifty all but one day, which we borrow from the world to come, at once the Eighth and the first, or rather one and indestructible. For the present sabbatism of our souls can find its cessation there, that a portion may be given to seven and also to eight  (so some of our predecessors have interpreted this passage of Solomon).
 They deify bad passions, and then act as if the gratification of them were an honour to the gods in whom they have personified them.
 The followers of Pythagoras swore by their master, who taught them the mystic properties of the number Four, which he called the Fountain of the Universe, because all things were made of four elements.
 The Simonians and Marcionites were two Gnostic sects, the one deriving its name from Simon Magus, the other from Marcion of Sinope. Simon, of whom we read in the Acts c. viii., is generally regarded by the Fathers as the precursor of the Gnostic Heresies. He maintained a system of Emanations from God, of which he claimed to be himself the chief. In his teaching the first cause of all things was an Ineffable Existence or Non-existence, which he sometimes called Silence and sometimes Fire, from which the Universe was generated by a series of six Emanations called Roots, which he arranged in pairs, male and female; and these six contained among them the whole Essence of his first Principle Silence. These Roots with Simon himself and his consort Helena, make up the Ogdoad referred to in the text. Marcion was a native of Sinope in Pontus, and flourished about the middle of the Second Century. His system of teaching was mainly rationalistic, and did not recognize (Dr. Mansel tells us, "Gnostic Heresies," p. 203) any theory of Emanations as connecting links between God and the world; for from his point of view the Supreme God was not, even indirectly, the Author of the world. It would seem that S. Gregory is confusing Marcion with Valentinus, and Egyptian heresiarch who flourished about the same time. In his theory we first find a system of "AEons," divided into an Ogdoad, a Decad, and a Dodecad. Or he may mean Marcus, a follower of Valentinus, and founder of the subordinate sect of the Marcosians.
 Exod. xii. 15.
 Ib. xxi. 2.
 Eccles. xi. 2. S. Gregory himself (Or. xviii. "in laudem Patris," c. 20) comments upon this passage as enjoining liberal almsgiving. S. Ambrose (in Luc. vi.) has a mystical interpretation somewhat resembling that here referred to: but I cannot find a predecessor of Gregory on the verse. Some later commentators, according to Cornelius and Lapide, take the Seven of the poor in this life, and the Eight of the souls in Purgatory, following a common interpretation of these numbers.
Reference address : https://www.elpenor.org/gregory-nazianzen/pentecost.asp?pg=2