I learned something new today while reading about the dedication of churches in light of today's feast. There are of course much symbolism in the dedication ceremony. One such aspect of this symbolism is that the new church symbolizes our souls. At first, our souls in original sin. Then, the bishop uses holy water on the church representing the regeneration of our soul in baptism. Then the church is anointed, symbolizing confirmation. Finally, although this isn't directly mentioned in the following text, I believe the Mass offered following the ceremony could represent the soul's first communion and or our souls being united with Christ and offered up in the Sacrifice of the Mass?? I didn't read that last part after the symbolism of confirmation, but I think it makes sense. Anyway, the following is the full text I read from the liturgical Year by Abbot Gueranger;
*edit: altar represents Christ our head.
The name of church given to the Christian temple signifies the assembly of the faithful—those who are validly baptized and profess the true Catholic Faith. The sanctification of the elect in its successive phases is the soul and inspiration of that most solemn of liturgical functions, the dedication of a church.
First of all, the temple with its bare walls and closed doors represents the human race created by God, and yet robbed of His presence ever since the original sin. But the heirs of the promise have not yielded to despair; they have fasted, they have prayed through the night; morning finds them sending up to God the supplication of the penitential psalms, the inspired expression of David's chastisement and repentance.
At early dawn Our Savior appears under the tent which has been raised before the closed doors, where the "exiled" faithful are praying. He is represented by the Bishop vesting in the sacred robes, as He clothed Himself with our flesh. The God-Man joins His brethren in their prayer; then, leading them to the still closed temple, He there prostrates with them and redoubles His supplications.
Then around the noble edifice, unconscious of its destinies, begins the patient strategy, wherewith the grace of God, and the ministers of that grace, undertake the siege of abandoned souls. Thrice the pontiff goes around the whole building, and thrice "attempts to force open" the obstinately closed doors; but his storming consists of prayers to Heaven, his force is but the merciful and respectful persuasion of devotion. At length the doors yield and an entrance is gained into the temple: "Peace eternal to this house, in the name of the Eternal!"
The Bishop, now within, continues to pray. His thoughts are intent upon the human race, symbolized by this future church. He knows that in its fallen state ignorance is its first evil. Accordingly he rises; and, on two lines of ashes running transversely from end to end of the temple and crossing in the center of the nave, he traces with his episcopal crozier the Greek and Latin alphabets, the elements of the two principal languages in which Scripture and Tradition are preserved. They are traced with the pastoral staff, on the cross formed by the ashes; because sacred science comes to us from doctrinal authority, because it is understood only by the humble, and because it is all summed up in Jesus Crucified.
Like the catechumen, the human race now enlightened requires, together with the temple, to be purified. The Bishop makes use of the loftiest Christian symbolism, in order to perfect the element of this purification which he has so much at heart: he mingles water and wine, ashes and salt, figures of the Humanity and the Divinity, of the Death and the Resurrection of Our Savior. As Christ preceded us in the waters of Baptism at the Jordan, the aspersions are begun at the altar and continued through the whole building.
In the order of the work of salvation, water is followed by oil, which confers on the Christian, in the Sacrament of Confirmation, the perfection of his supernatural being; and which also makes kings, priests, and pontiffs. For all these reasons, the holy oil now flows copiously over the altar, which represents Christ our Head, Pontiff and King, that it may afterwards, like the water, find its way to the walls of the entire church. Truly is this temple henceforth worthy of the name of church; for thus "baptized" and consecrated, with the God-Man, by water and the Holy Ghost, the stones of which it is built represent perfectly the faithful, who are bound together and to the divine Corner-Stone by the imperishable cement of charity.
The sacred chants which, since the beginning of the solemn function, have not ceased to enhance its sublime developments, now redouble in enthusiasm; and rising to the full height of the mystery, they hail the church, now so intimately associated to the altar as the bride of the Lamb. From this altar ascend clouds of incense, which, mounting to the roof and billowing down the nave, fill the whole temple with the perfumes of the Spouse. And now the subdeacons come forward, presenting for the Bishop's blessing the gifts made to the Bride on this great day, and the vesture She has prepared for Herself and for the Lord.
In the early Middle Ages, it was only at this point that the triumphant translation of the relics destined to be placed in the altar took place, after having remained all this time in the tent outside, as it were in exile. In the West, up to the 13th century and even later, the Sacred Body of Our Lord Himself in the Holy Eucharist was sealed up in the altar with the relics of the Saints. It was the "Church united to the Redeemer, the Bride to the Bridegroom," says St. Peter Damian; it was the final consummation, the passage from time to eternity. Then follows the Mass of the Dedication, solemnly offered by the Bishop.
In not too distant times, the anniversary of its dedication was celebrated by each church. In some countries, a single day was set aside to celebrate the dedication of all the churches of that nation. In the traditional Latin Liturgy, the Anniversaries of some of the greatest churches are celebrated by the Universal Church: St. Mary Major (Our Lady of the Snows) on August 5, St. Michael the Archangel on September 29, the Archbasilica of Our Savior (St. John Lateran) on November 9, and the Basilicas of St. Peter (the Vatican) and St. Paul outside the Walls on November 18. The Liturgy for the first of these is really a Feast of Our Lady; that of the second, a Feast of St. Michael and all the Holy Angels. The Liturgy for the last two dates is truly that of the anniversary of dedication.