Commentaria in Leviticum
Mystically, fire is a symbol of chastity and divine purity, which men, above all priests, ought to imitate. Hence at Rome the Vestal virgins kept with equal observance the sacred fire and their chastity; and the fire itself, the symbol alike of life and of chastity, they called Vesta; for so Ovid sings of it in the Fasti:
…“Nor do thou understand Vesta to be aught else than pure flame;”
And thou seest no bodies born from flame. Rightly then is she a virgin, who sends back no seeds, and receives none, and loves the companions of virginity.
Of this sacred fire and its keepers Virgil also sings, Aeneid 4:
And he had consecrated the watchful fire, the eternal vigils of the gods.
If Christians keep and increase this fire, they shall not fear that fire of which it is written in Deuteronomy, chapter 31: “A fire is kindled in my wrath, and shall burn even to the lowest hell.”
Secondly, fire is the Holy Spirit, who on the day of Pentecost descended in the form of fire upon the Apostles and the Church, and ever remains with her, as He had descended before upon Christ, John 1:33. So Hesychius and Radulphus. How this fire ought to be nourished I said in chapter 6, verse 12. Further, how apt a symbol fire is of God, of the Holy Spirit, and of charity, hear. First, fire is as it were omnipotent, because it softens iron and melts all metals. Such is God, and charity. Second, fire, if it be an enemy, is terrible and to be dreaded, as is plain in conflagrations and lightnings; but if a friend, it is supremely beneficent: for fire cooks food, and softens everything, even the hardest, for man. Third, fire in darkness gives guidance and refuge. Fourth, fire burns him who handles it, warms him who stands by: so with God we must deal from afar and reverently. Fifth, fire is never idle and languid, but lively and active. Sixth, fire lies hidden in the secret veins of flint: so God is innermost and hidden in created things. Seventh, fire is bright and shining, especially in darkness. Eighth, fire is separate from every other thing and most pure, nor is there anything in it that is not fire; nay, it purifies gold, silver and other metals. Ninth, fire is increased by other things the more Tenth, the union of the supreme wisdom, goodness and power of God is wonderfully expressed in the light, heat and efficacy of fire. Eleventh, fire breaks and hardens some things, loosens and dissolves others: so God “hath mercy on whom he will, and whom he will he hardeneth,” Romans, chapter 9, verse 18. Twelfth, fire by liquefying unites and joins together many things divided among themselves: so God unites all nations in His faith and spirit. Thirteenth, fire warms even water, which is contrary to it: so God does good even to His enemies. Fourteenth, fire tends upward, as if to say, I am heavenly; hence it has greater efficacy upward than downward. Fifteenth, fire liquefies some things, does not warm others, as the diamond and the carbuncle; some things it turns into smoke, some into embers, some into ashes, some into lime: so various is the operation of God and of the Holy Spirit. Sixteenth, as from fire flow light and heat, so from the Father flow the Son and the Holy Spirit, says Damascene, book 1 On the Faith, chapter 9. Finally, this fire of the altar as it were consecrated and sanctified both the victims and the offerers. Rightly therefore did Heraclitus say that God is intelligible fire. Finally, let priests here note of how great dignity the sacrifices are, since the glory of the Lord insinuates itself and is shown in them, and consequently with how reverent, sublime and heavenly a mind they ought to offer them. Hear St. Chrysostom, book 6 On the Priesthood: “At that time (of the sacrifice) angels sit by the priest, and the whole order of the heavenly powers raises cries, and the place near the altar is full of choirs of angels in honour of Him who is immolated. For a certain admirable old man saw at that time a multitude of angels clothed in shining garments surrounding the altar itself, and bowing their heads as one sees soldiers standing in the presence of the king.”
So Abbot St. Euthymius, about the year of Christ 503, when sacrificing, often saw angels ministering with him to God and handling the sacred things. At other times he saw fire and an immense light descending from above, which embraced him together with his minister to the end of the sacrifice: Cyril is witness in his Life. So the Holy Spirit in the form of fire surrounded St. Anastasius while he sacrificed, as is had in the Life of St. Basil.
So St. Basil did not perform the sacrifice unless a divine vision were shown him; and when on one occasion it was denied him on account of a deacon’s wanton glance, he removed him from the altar, and presently, the vision returning, completed the sacrifice. At other times he was seen while sacrificing to be surrounded with a most brilliant light and with angels in white: Amphilochius is witness in his Life.
So St. Gudwal, who five hundred years ago was an archbishop, having first constantly prepared with fasts, vigils and prayers, saw while celebrating the heavens opened, the angels descending and singing praises to God with great reverence; and he himself stood like a splendid column of light, handling the Holy of Holies and immolating the Lamb of God.
So over the head of St. Martin, while he sacrificed, a globe of fire appeared, as Severus testifies.
So the priest St. Plegilus, while sacrificing, saw Christ in the form of a child in the consecrated host, offering Himself to him for embraces and kisses: Paschasius of Corbie is witness, in his book On the Body and Blood of the Lord, chapter 14.
Wonderful also are the things which St. Gregory relates, homily 37 on the Gospels, of St. Cassius, Bishop of Narni, who celebrated constantly.
John Moschus, in the Spiritual Meadow, chapter 199, commemorates an old man who while sacrificing saw angels standing by him on the right and on the left. The same, chapter 4, relates that Abbot Leontius saw an angel standing at the right horn of the altar, who said to him: “Since this altar was sanctified, I have been commanded to stand continually by it.” Exactly the same was seen and heard by Abbot Barnabas; in the same place, chapter 10.
Palladius, in the Lausiac History, chapter 72, writes that Ammonas saw an angel marking those who came worthily to the holy Synaxis, and that those whom he had blotted out died after three days.