When from time to time I attend the Divine Liturgy, and am inspired to read over those holy rites again (as I have been doing all week), I am always struck anew by the words of the sticheron sung after Communion:
Εἴδομεν τὸ φῶς τὸ ἀληθινόν, ἐλάβομεν Πνεῦμα ἐπουράνιον, εὕρομεν πίστιν ἀληθῆ, ἀδιαίρετον Τριάδα προσκυνοῦντες, αὕτη γὰρ ἡμᾶς ἔσωσεν.
We have seen the true light, we have received the heavenly [lit. super-celestial] Spirit, we have found the true Faith, worshipping the undivided [or: indivisible] Trinity: for This [i.e. the Trinity] hath saved us.
Видехом свет истинный, прияхом Духа Небеснаго, обретохом веру истинную, нераздельней Троице покланяемся, Та бо нас спасла есть.
The Latin edition of the Catechism quotes this text as Vidimus verum Lumen, Spiritum recepimus cælestem, veram fidem invenimus: Trinitatem adoramus indivisibilem quia Ipsa nos salvavit – however, I wonder why it does not more exactly reproduce the word order of the Greek original, nor correctly render προσκυνοῦντες, originally "kissing towards" (in the sense of prostrating oneself in an act of obeisance), later meaning "venerating", as adorantes, "worshipping", not to say procidentes, "falling down before (in worship)" rather than representing it as adoramus, "we worship".
Surely Vidimus lumen verum, recepimus Spiritum (super)cælestem, invenimus fidem veram, indivisibilem Trinitatem adorantes, quia ipsa nos salvavit would be a closer rendering? The vital point is that it is in worshipping the Trinity that we have seen the true light, received the Spirit, found the Faith: various translations try and emphasise this, phrasing it "by worshipping" or "as we worship". Or, better, let the whole sticheron be reversed: the Trinity has deigned, via the all-wise plan or economy of salvation, to have saved us – worshipping the Same, we have found the true Faith, we have been gifted with the Uncreated Gift of the Holy Ghost, Uncreated Grace engendering supernatural grace that uplifts us beyond our merely natural capacities to become capax Dei; yes, we have beheld the true Light, Who is Christ.
This pregnant passage, which is originally a sticheron sung at Pentecost Vespers, has always struck me as somehow not quite ad rem at Communion in the narrow sense. After all, "see[ing] the true light" is if anything more a reference to the Sacrament of Enlightenment, Photismos, that is, Baptism; and "receive[ing] the heavenly Spirit" is likewise more directly a reference to Baptism and Confirmation (which in the East are normally celebrated together). The words fit more directly to the Eastern view of Pentecost as not so much a celebration of the Descent of the Holy Ghost, as of the definitive revelation of the Trinity: participating in this in worship, which both instantiates and transcends the historical event recalled, is to find "the true Faith".
What then of its possible application at Communion time? Of course, Christ is the Light of the world, and we "see" Him in the Sacrament, the Realsymbol of His Real Presence; of course, in receiving Christ, we do receive the Holy Spirit, since no Person of the Trinity is ever without the others, by reason of their perichoresis, their circumincession; of course – in all sacraments and every prayer, above all in the Divine Mysteries that is the Liturgy par excellence – we do find "the true Faith" in "worshipping the undivided Trinity" Who "hath saved us"; but one feels that this is to receive this sacred text an accommodated sense.
Sure enough, the use of this sticheron at every Divine Liturgy (outside of Paschaltide, when different texts are employed) turns out to be a 17th or 18th century addition to the Liturgy – the carefully-preserved liturgical books of the Old Believers know nothing of its use, and it makes its first appearance in the Divine Liturgy in the famous (not to say notorious) liturgicon promulgated by Patriarch Nikon in 1655 for the Russian Church. It did not appear in Greek liturgical books till later; curious, since Nikon was motivated by a mania to conform the Russian Rite to the Greek, not knowing that the Russian Rite in fact preserved an older and arguably purer form of the Byzantine Rite, which the Greeks had innovated away.
There was a strong tendency, especially in those centuries, to interpret each part of the Divine Liturgy as symbolic of some part of Our Lord's life (just as mediæval Westerners likewise allegorised the Roman Mass): the Communion was viewed as symbolic of the Resurrection and Ascension, and of the sending down the Holy Ghost – perhaps this engendered the desire to sing a most appropriate sticheron of Pentecost to cement this understanding.
I find personally that the choral exclamation "We have seen the true light", in its triumphant proclamation of orthodoxy – literally, right worship (of the Trinity) – in the joyful proclamation of adherence to the one true Faith, and indeed sums up the experience of Byzantine worship as an uplifting and sanctifying participation in the life of heaven, a glimpse of the divine beauty. It seems redolent of what Orthodoxy means in all its purity, as also in its prominent references to Christ our God and to the Holy Spirit, paralleling those distinctive emphases of Eastern worship.
Could not the ambassadors sent by Grand Prince Vladimir of Kiev, later to be canonised as St Vladimir, the Enlightener of Russia, having beheld the worship of the Great Church of Hagia Sophia, have cried out in exactly these words? "We have seen the true light, we have received the heavenly Spirit, we have found the true Faith, worshipping the undivided Trinity: for This hath saved us."