St Gregory of Nyssa prefaces his homilies on the Song of Songs with these words:
Greetings in the Lord to Olympias, most worth of reverence, from Gregory the bishop of Nyssa.Taken from this edition.
I have approved your zeal concerning the Song of Songs, with which you have instructed me in person and by letters, as appropriate to your reverent life and pure soul, so that by the appropriate insight there may be manifested the philosophy hidden in the words, cleansed of the obvious meaning of the text as it stands in simple sense of the words. Therefore I have eagerly accepted your concern about this, not as if it could be useful to you in terms of morals (I am persuaded that the eye of your soul is pure from any perception sullied by passion and that it is able to look without embarrassment toward simply grace through these divine words), but so that those more fleshly than you are might have guidance toward the spiritual and immaterial condition of the soul toward which this book leads through its hidden wisdom.
Because it seems to some churchman that the letter of sacred Scripture is always to be adhered to, and they do not admit that anything at all useful to us in it is said by means of riddles and deeper meanings, I first conisder it necessary to respond to those who accuse us of these things and to show that we are not out of line in searching out in every way possible what is useful in the divinely inspired scripture (see 2 Tim 3:16). Even if the letter, as it is called, should be somewhat useful to the reader (since it readily yields the meaning one is concerned with), if something is spoken that is concealed in deeper meaning and riddles, it is idle in its usefulness to us as far as the immediate sense is concerned. For this reason, the Logos educating us through Proverbs guides us to ponder such words, so as to understand whether what is said is spoken as "a proverb," as "a figure," as a "word of the wise," or as "riddles" (see Prov 1:6).
We shall not quibble over which term – "insight (theoria) through elevation," figurative interpretation," "allegory," or whatever else one chooses to call it – as long as that term is joined to useful concepts. The great Apostle himself, saying that "the law is spiritual" (Rom 7:14), included in the word "law" even the historical narratives, for all divinely inspired Scripture is law to those reading it, educating not only through manifest words of command but through historical narratives to knowledge of mysteries and to pure behavior those who attend to it carefully. Paul used it in his interpretation as it seemed best to him, looking toward what is useful. He did not bother about what terms he used to describe this form of interpretation. But how he says that the phrase changes, as he is about to translate the history into demonstration of the dispensation of the two covenants. When he mentions the two children of Abraham, those born to him from bondage and from freedom, he calls the insight concerning them "allegory" (see Gal 4:24). Again, narrating something from history, he says: "These things happened to them in a typical way, but they were written down for our exhortation" (1 Cor 10:11). Again, when he said: "You shall not muzzle an ox when it is treating out the grain," he added "It is for oxen that God is concerned? Does he not speak entirely for our sake?" (see 1 Cor 13:12). Again, the transition from corporeal things to those that are intellectual he calls "turning to the Lord" and "lifting the veil" (see 2 Cor 3:16).
Nevertheless, in all these diverse ways and terms for the insight according to the intellect, he guides us to one form of teaching: we must not stay altogether at the concrete reality because the immediate sense of things said often harms us when it comes to a virtuous manner of life, but we must remove ourselves to the immaterial and intellectual insight, so that those senses that are a little more corporeal might be translated into intellect and thought, having shaken out the dust that settles on account of the more corporeal appearance of what is said. Therefore he said, "the letter kills, but the spirit gives life" (2 Cor 3:6), since often if we were to stand in the mere concrete realities of the history, it would offer us no patterns at all of the good life. How is hearing that Hosea the prophet begot children by a prostitute (Hos 1:2) useful for virtue, or that Isaiah went into the prophetess (Isa 8:3), unless someone should move beyond the letter of what is said? Or how do the narratives about David contribute to a virtuous life, when adultery and murder in the same case have coincided in one pollution? But if some reason should be found, which would show that what was arranged through these things was guiltless, then his words would be demonstrated to be all the more true that "the letter kills" (for it contains in itself the patterns of wicked behavior), "but the spirit gives life" (2 Cor 3:6), for it transforms the superficial and blameworthy sense into more divine meanings.