The Exaltation of the Cross
The Exaltation of the Cross, celebrated on the fourteenth of September, commemorates the finding of Christ's Cross by Saint Helen, the mother of the Emperor Constantine in the fourth century; and, after it was taken by the Persians, of its recovery by the Emperor Heraclius in the seventh century at which time it was "elevated" in the Church of the Resurrection in Jerusalem. From this latter event the "universal elevation" of the Cross was celebrated annually in all of the churches of the Christian Empire.
The day of the Elevation of the Cross became, as it were, the national holiday of the Eastern Christian Empire similar to Independence Day in the United States. The Cross, the official emblem of the Empire which was placed on all public buildings and uniforms, was officially elevated on this day by the bishops and priests. They blessed the four directions of the universe with the Cross, while the faithful repeated the chanting of "Lord have mercy." This ritual is still done in the churches today after the solemn presentation and elevation of the Cross at the end of the Vigil service of the holy day following the Great Doxology of Matins.
The troparion hymn of the feast which was, one might say, the "national anthem" sung on all public occasions in the Christian Empires of Byzantium and Russia, originally petitioned God to save the people, to grant victory in war and to preserve the empire "by the power of Thy Cross." Today the troparion, and all the hymns of the day, are "spiritualized" as the "adversaries" become the spiritually wicked and sinful including the devil and his armies, and "Thy people" replace the names of ruling officials of the Empire.
The holy day of the Elevation of the Cross, although it has an obviously "political" origin, has a place of great significance in the Church today. It remains with us as a day of fasting and prayer, a day when we recall that the Cross is the only sign worthy of our total allegiance, and that our salvation comes not by "victories" of any earthly sort but by the only true and lasting victory of the crucifixion of Christ and our co-crucifixion with him.
When we elevate the Cross and bow down before it in veneration and worship to God, we proclaim that we belong to the Kingdom "not of this world," and that our only true and enduring citizenship is with the saints in the "city of God" (Ephesians 2:19; Hebrews 11:10; Revelation 21-22).
— Fr. Thomas Hopko, The Orthodox Faith (read more)