Today, the 3rd Sunday of Great Lent, we celebrate the veneration of the precious and Life-giving Cross, about which the Apostle Paul wrote, ‘But God forbid that I should glory, save in the cross of our Lord Jesus Christ, by whom the world is crucified unto me, and I unto the world’ (Galatians 6:14). The hymnography for this Sunday refers to the Cross as ‘the fair paradise of the Church’ and the ‘Tree of incorruption that brings us the enjoyment of eternal glory’, ‘an invincible weapon, an unbroken stronghold’, the ‘unconquerable tropy of the true faith, door to Paradise, succour of the faithful, [and] rampart set about the Church.’ 
It may seem curious to note that this commemoration is something distinct from the commemoration of ‘Good Friday’—that is, the commemoration of the Passion and Death of our Lord on the Cross. The two are, of course, directly connected though. The Cross does not have some kind of magical potency apart from its role as the instrument of our Lord’s Passion. As the Synaxarion for this Sunday states, ‘The Cross reminds us of the Passion of our Lord, and by presenting to us His example, it encourages us to follow Him in struggle and sacrifice, being refreshed, assured, and comforted.’ 
Furthermore, it is not accidental that the Life-giving Cross is commemorated half-way through Lent. The Synaxarion tells us:
As they who walk on a long and hard way and are bowed down by fatigue find great relief and strengthening under the cool shade of a leafy tree, so do we find comfort, refreshment, and rejuvenation under the Life-giving Cross, which our Holy Fathers “planted” on this Sunday. Thus, we are fortified and enabled to continue our Lenten journey with a light step, rested and encouraged. 
It is important to note that this Cross in which we find comfort and refreshment is not merely an historical object or event, but something fundamental to the cosmos itself. I was struck several years ago by an observation in Fr John Behr’s profound little book, The Mystery of Christ: Life in Death:
Theologically speaking, creation and its history begins with the Passion of Christ and from this ‘once for all’ work looks backwards and forwards to see everything in this light, making everything new. Christian cosmology, elaborated as it must be from the perspective of the Cross, sees the Cross as impregnated in the very structure of creation: stat crux dum volvitur orbis—the Cross stands, while the earth revolves. 
Fr John then quotes from the ‘Second Part’ of St Isaac the Syrian to support his point:
We do not speak of a power in the Cross that is any different from that through which the worlds came into being, [a power] which is eternal and without beginning and which guides creation all the time without any break, in a divine way and beyond the understanding of all, in accordance with the will of his divinity. 
Thus, it is no surprise that the Holy Fathers discover the Cross throughout all of Scripture, prefigured in the Old Testament and gazed back at in the Book of Revelation. Indeed, it can fairly be said that the pattern of the Cross, or what St Gregory Palamas calls ‘the mystery of the Cross’, is fundamental to patristic exegesis.  Thus, St Gregory begins his homily for this Sunday with the characteristic comment, ‘The Cross of Christ was mysteriously proclaimed in advance and foreshadowed from generations of old and no one was ever reconciled with God except by the power of the Cross.’  As Fr Georges Florovsky has put it, ‘The mystery of the Cross begins in eternity, “in the sanctuary of the Holy Trinity, unapproachable for creatures.”’ 
The Latin phrase Fr John qutoes above is the motto of the Roman Catholic ‘Carthusian’ Order, an order of semi-erimitic contemplative monks that originated in the mountains of France  whose symbol is a sphere surmounted by a Cross. The same symbol, whether a nod toward the Carthusians or not, forms the central image of G.K. Chesterton’s fascinating novel, The Ball & the Cross, where the ‘ball’ atop St Paul’s Cathedral in London is claimed by Lucifer as the symbol of rationalism, while the ‘cross’ is claimed by the old Bulgarian monk, Fr Michael as the symbol of Christianity. At one point, Fr Michael tells a ‘parable’ to illustrate the folly of Lucifer’s hatred of the cross:
‘I once knew a man like you, Lucifer,’ he said, with a maddening monotony and slowness of articulation. ‘He took this----’
‘There is no man like me,’ cried Lucifer, with a violence that shook the ship.
‘As I was observing,’ continued Michael, ‘this man also took the view that the symbol of Christianity was a symbol of savagery and all unreason. His history is rather amusing. It is also a perfect allegory of what happens to rationalists like yourself. He began, of course, by refusing to allow a crucifix in his house, or round his wife's neck, or even in a picture. He said, as you say, that it was an arbitrary and fantastic shape, that it was a monstrosity, loved because it was paradoxical. Then he began to grow fiercer and more eccentric; he would batter the crosses by the roadside; for he lived in a Roman Catholic country. Finally in a height of frenzy he climbed the steeple of the Parish Church and tore down the cross, waving it in the air, and uttering wild soliloquies up there under the stars. Then one still summer evening as he was wending his way homewards, along a lane, the devil of his madness came upon him with a violence and transfiguration which changes the world. He was standing smoking, for a moment, in the front of an interminable line of palings, when his eyes were opened. Not a light shifted, not a leaf stirred, but he saw as if by a sudden change in the eyesight that this paling was an army of innumerable crosses linked together over hill and dale. And he whirled up his heavy stick and went at it as if at an army. Mile after mile along his homeward path he broke it down and tore it up. For he hated the cross and every paling is a wall of crosses. When he returned to his house he was a literal madman. He sat upon a chair and then started up from it for the cross-bars of the carpentry repeated the intolerable image. He flung himself upon a bed only to remember that this, too, like all workmanlike things, was constructed on the accursed plan. He broke his furniture because it was made of crosses. He burnt his house because it was made of crosses. He was found in the river.’ 
Interestingly, The Ball & the Cross turns up a bit unexpectedly in an Orthodox reflection on the Cross: in a 1977 article entitled ‘From the Perspective of the Cross’, Hieromonk Roman (Braga) talks about the very shape of the Cross as indicative of man’s place in the universe. It is worth quoting at some length:
The cross is the axis of two coordinates that establishes man’s place in the universe. Man is at the point of intersection between the vertical plane, which is transcendent, and the horizontal one, which is limited, historic, inherent.
Man is the theandric mode of existence in which God and nature must be combined in a harmonious synthesis. But at the same time, man’s being on the cross is a paradox, an enigma—not for the Creator, Who knew what He did when He created man, but for himself.
If we think of the cross, this imaginary axis, as the intersection of two existential planes completely different from one another—matter and spirit, existence and nonexistence, God and nothingness—then surely at the intersection point, that is, in man, any kind of logic becomes impossible and absurd. Nevertheless, man is the only thinking reality in the world. Why? Because true thinking is in a way paradoxical; it is born of contradictory situations. Once G.K. Chesterton, looking at the dome of St Paul’s Cathedral in London where the cross is atop a sphere, made a remark that can be considered to be the foundation of the theology of the cross. He said that the sphere, which is the Greek symbol of perfection, is limited to itself. Traveling around the sphere, one reaches nowhere. This is the image of philosophy—it is a closed system, it cannot go out of its dogmatic antithesis. On the other hand, developing a mode of thinking in a cross-like manner gives the world an infinite freedom—on the one hand, growing in God, or ascending on the vertical plane, and on the other hand, the freedom of descending into the total abyss, into total negativism. 
These are just a few thoughts about the centrality of the Cross to our faith. Unfortunately, time does not suffice for me to begin to delve into the coincidence of the Sunday of the Cross with the Feast of the Annunciation this year, so I shall simply conclude with the tenth stanza of St Ephraim the Syrian’s Hymn XII on Paradise:
Because Adam touched the Tree
he had to run to the fig;
he became like the fig tree,
being clothed in its vesture:
Adam, like some tree,
blossomed with leaves.
Then he came to that glorious
tree of the Cross,
put on glory from it,
acquired radiance from it,
heard from it the truth
that he would return to Eden once more. 
 From the Stichera in Tone Five at Lord, I have cried at Great Vespers, in The Lenten Triodion, tr. Mother Maria & Archimandrite [now Metropolitan] Kallistos (Ware) (South Canaan, PA: STOTS, 1994), pp. 334-335.
 Synaxarion of the Lenten Triodion & Pentecostarion, ed. Fr David (Kidd) & Mother Gabriella (Ursache) (Rives Junction, MI: HDM, 1999), p. 78.
 Ibid., p. 79.
 Fr John Behr, The Mystery of Christ: Life in Death (Crestwood, NY: SVS, 2006), p. 90.
 Qtd. in ibid., p. 90.
 St Gregory Palamas, The Homilies, ed. & tr. Christopher Veniamin, with The Monastery of St John the Baptist (Waymart, PA: Mount Thabor, 2009), p. 79.
 Ibid., p. 74.
 Protopresbyter Georges Florovsky, Creation & Redemption, Vol. 3 in the Collected Works of Georges Florovsky (Belmont, MA: Nordland, 1976), p. 100.
 I’m not certain of the origin of the motto, however.
 G.K. Chesterton, The Ball & the Cross (NY: Dover, 1995), p. 6.
 Hieromonk Roman (Braga), ‘From the Perspective of the Cross’, Divine Ascent: A Journal of Orthodox Faith 1:2 (Exaltation of the Holy Cross 1997), pp. 69-70. I must admit that I am not completely certain of precisely to what passage in GKC Fr Roman is referring. His comments are reminiscent of the conversation between Lucifer and Fr Michael, but not an exact match.
For those unfamiliar with this 20th-c. Romanian confessor for the faith, I highly recommend this interview with him from PBS’s Frontline.
 St Ephraim the Syrian, Hymns on Paradise, tr. Sebastian Brock (Crestwood, NY: SVS, 1990), p. 164.