First go to A Few Remarks on the Traditional Procedure for the Recognition of Saints in Orthodoxy.
And here are some excerpts from a couple of online articles. The point is that incorrupt relics are tied in mystical participation to the Resurrection of Christ, from which their whole theosis arises.
From Why Relics?:
The veneration of saints is vital to the life of the Holy Orthodox Church, because the existence of saints affirms that it is truly possible to fulfill the Christian vocation --- to become conformed to the image of Christ --- because every Christian is called to be a saint, for Christ commanded us to be perfect as our heavenly Father is perfect.The theology of the icon is in part also the theology of the veneration of saints' relics and their frequent incorruption --- in essence, that the body participates in the process of transfiguration / sanctification / deification / theosis --- different words for the same process of salvation.
The veneration of saints' relics and their frequent incorruption affirm that the physical world indeed does have the potential for being transfigured and resurrected, as it participates in the restoration of humanity to the beauty of the Divine Image and Likeness. That the physical world participates in the process of sanctification is a fundamental element of Orthodox spiritual theology, and is an underlying principle in both the theology of icons and the theology of the veneration of saints' relics. In this, Orthodoxy diverges to some extent from Roman Catholic theology, and diverges enormously from Protestant theology, which vehemently denies the possibility of the deification (theosis) of humans or the sanctification of the material world. However, it is exactly these very principles (of theosis and sanctification of the physical world), that are manifested and achieved during the years of ascetic and spiritual experiences practiced by so many of the saints, that accounts for the widespread occurrence of the incorruption of saints' bodies. Basically, the saints bodies were so transfigured and deified by their sanctity, that even after their souls separated from their bodies, the elevated sanctity of their bodies remained, so that their flesh did not decompose, and their bodies exude a sweet fragrance. However, even for most of the saints, to whom the gift of incorruption was not given, their bones still exude the miraculous power of the first-fruits of the resurrection and of the Kingdom of God.
Incorruption of relics, like icons, affirm that the physical world indeed DOES have the potential for being transfigured and resurrected, as it participates in the restoration of humanity to the beauty of the Divine Image and Likeness. The sanctified and transfigured bodies of the saints, (whether or not they are incorrupt), are so powerful that numerous miracles occur by means of the saint's relics, or even by being annointed with oil from the lamps burning by their relics, or from soil from the ground where the saints are or were buried. Of course, most of the saints were also vehicles of miracles while they were yet in their bodies, and this miraculous grace continues to flow from them after their repose.
The physical world was created good and the process of the transfiguration of the world, which is the end purpose of the Orthodox Christian life and struggles, is part of the process of the transfiguration and salvation of each person. The incorruption of saints' bodies and the miracles performed through the relics of saints is a foretaste or firstfruits of the restoration of the world to the way in which God created it.
St. Justin Popovich, The Place of Holy Relics in the Orthodox Church:
The holiness of the Saints--both the holiness of their souls and of their bodies--derives from their zealous grace- and virtue-bestowing lives in the Body of the Church of Christ, of the God-Man. In this sense, holiness completely envelopes the human person--the entire soul and body and all that enters into the mystical composition of the human body. The holiness of the Saints does not hold forth only in their souls, but it necessarily extends to their bodies; so it is that both the body and the soul of a saint are sanctified. Thus we, in piously venerating the Saints, also venerate the entire person, in this manner not separating the holy soul from the holy body. Our pious veneration of the Saints' relics is a natural part of our pious respect for and prayerful entreaty to the Saints. All of this constitutes one indivisible ascetic act, just as the soul and body constitute the single, indivisible person of the Saint. Clearly, during his life on the earth, the Saint, by a continuous and singular grace- and virtue-bestowing synergy of soul and body, attains to the sanctification of his person, filling both the soul and body with the grace of the Holy Spirit and so transforming them into vessels of the holy mysteries and holy virtues. It is completely natural, again, to show pious reverence both to the former and to the latter, both to soul and body, both of them holy vessels of God's grace. When the charismatic power of Christ issues forth, it makes Grace-filled all the constituent parts of the human person and the person in his entirety. By unceasing enactment of the ascetic efforts set forth in the Gospels, Saints gradually fill themselves with the Holy Spirit, so that their sacred bodies, according to the word of the holy Apostle, become temples of the Holy Spirit (I Corinthians 6:19; 3:17), Christ dwelling by faith in their hearts (Ephesians 3:17) and by fruitful love also fulfilling the commandments of God the Father. Establishing themselves in the Holy Spirit through grace-bestowing ascetic labors, the Saints participate in the life of the Trinity, becoming sons of the Holy Trinity, temples of the Living God (II Corinthians 6:16); their whole lives thus flow from the Father, through the Son, in the Holy Spirit. By piously venerating the holy relics of the Saints, the Church reveres them as temples of the Holy Spirit, temples of the Living God, in which God dwells by Grace even after the earthly death of the Saints. And by His most wise and good Will, God creates miracles in and through these relics. Moreover, the miracles which derive from the holy relics witness also to the fact that their pious veneration by the people is pleasing to God.
Archpriest Vasily Demidov, On the Veneration of the Holy Relics and Remains of the Saints:
"God made not death: neither hath He pleasure in the destruction of the living" (Wisdom 1:13). "God created man for incorruption and made him to be an image of His own eternity" (Wisdom 2:23). Corruption appeared after the fall. "Through the hatred of the devil death entered he world" (Wisdom 2:24). "Righteousness is immortal, but injustice causeth death" (Wisdom 1:15). "For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord (Rom. 6:23). As a result of the fall, the fate of man was altered. After death, his dust returned to the earth from which it had been taken, and his spirit returned to God Who had bestowed it (Eccl. 12:7). Therefore, the bodies of all men, both righteous and sinful, are interred in the earth. But the bodies of certain "friends of God," in accordance with His will, escape the universal corruption and remain, at times whole, at times partially intact. Death is the common rule for all that live. However, the words of the Bible point out to us the exceptions to this law. Enoch and Elias, born on earth and subject to the common law of death, did not die; but having conquered the law of death, they were transported to the Kingdom of Heaven while yet in the body. The accounts of their translation and present state are recorded in Genesis 5:4 and III Kings 2. In the course of so great a time these righteous men have remained in that degree of growth in which they were taken up, in accordance with the special Providence of God. They have teeth, a stomach, reproductive members, even though they have no need of food or wives. . . .Posted by Clifton at February 8, 2005 12:01 PM | TrackBackAs the struggles of Christians are not the same, but of various sorts, so also their glorification after death may take many forms. "There is one glory of the sun, and another glory of the moon, and another glory of the stars; for one star differeth from another star in glory" (I Cor. 15:41). Gifts of grace are also given to people in different degrees, although they flow from the same source. "Now there are diversities of gifts, but the same Spirit... Who worketh all in all" (I Cor. 12:4, 6).
According to the testimony of the ancient, apostolic Church, "We receive the witness of men" (I St. John 5:9). The relics of the prophets Isaiah, Jeremiah, Obadiah, Zachariah and several of the apostles remained incorrupt. The relics of the holy Prophet Elisha, as we see from the Fourth Book of Kings, were preserved as bones.
Christians of the second century reverently gathered the remains of those who were martyred for Christ—Ignatius the God-bearer, Polycarp of Smyrna, Irenaeus of Lyons—and they constructed churches over them when freedom was given to Christianity; they erected altars and tables of oblation, and celebrated the Eucharist over their graves. By the word "relic" the ancient Christians always understood either an entire body preserved incorrupt or a portion thereof, or even the bones of the holy Saints, since the executioners quite often cut the Christians they had slaughtered in pieces, throwing them to the wild beasts to be devoured. What remained of the bodies of the martyrs, the Christians gathered with profound reverence and with hymns of prayer, often bribing those on guard with gold, and at such gatherings the annals and accounts of the heroes who endured torture and death for the name of Christ were read. Russian Christians, emulating the ancient forms of worship of the Greek Christians, have prayerfully honored their own ascetics who strove in the arena of life to receive a crown (I Cor. 9:24-25), and have glorified them, for the Holy Scriptures say: "I will... honor them that honor Me" (I Kings 2:30).
A Russian chronicler, narrating his account of the construction of the Cathedral of the Dormition in Moscow (A.D. 1472), reports the following: "They found [Metropolitan] Jonah to be incorrupt; but Photius had decayed in part, and Cyprian had decayed completely, leaving only bones."