The Following is an excerpt from Great Lent , by Alexander Schmemann
From Chapter 2: Preparation for Lent
 Finally comes the last day [of preparation for Lent], usually called "Forgiveness Sunday," but whose other liturgical name must also be remembered: the "Expulsion of Adam from the Paradise of Bliss." This name summarizes indeed the entire preparation for Lent. By now we know that man was created for paradise, for knowledge of God and communion with Him. Man's sin has deprived him of that blessed life and his existence on earth is exile. Christ, the Savior of the world, opens the door of paradise to everyone who follows Him, and the Church, by revealing to us the beauty of the Kingdom, makes our life a pilgrimage toward our heavenly fatherland. Thus, at the beginning of Lent, we are like Adam:
Adam was expelled form paradise through food;
Sitting, therefore, in front of it he cried:
"Woe to me....
One commandment of God have I transgressed,
depriving myself of all that is good;
Paradise holy! Planted for me,
And now because of Eve closed to me;
Pray to thy Creator and mine that I may be filled again by thy blossom."
Then answered the Savior to him:
"I wish not my creation to perish;
I desire it to be saved and to know the truth;
For I will not turn away him who comes to Me....
Lent is the liberation of our enslavement to sin, from the prison of "this world." And the Gspel lesson of this last Sunday (Matt. 6:14-21) sets the conditions for that liberation. The first one is fasting-- the refusal to accept the desires and urges of our fallen nature as normal, the effort to free ourselves from the dictatorship of flesh and matter over the spirit. To be effective, however, our fast must not be hypocritical, a "showing off." We must "appear not unto men to fast but to our Father who is in secret." The second condition is forgiveness-- "If you forgive men their trespasses, your Heavenly Father will also forgive you." The triumph of sin, the main sign of its rule over the world, is division, opposition, separation, hatred. Therefore, the first break through this fortress of sin is forgiveness: the return to unity, solidarity, love. To forgive is to put between me and my "enemy" the radiant forgiveness of God Himself. To forgive is to reject the hopeless "dead-ends" of human relations and to refer them to Christ. Forgiveness is truly a "breakthrough" of the Kingdom into this sinful and fallen world.
Lent actually begins at Vespers of that Sunday. This unique service, so deep and beautiful, is absent from so many of our churches! Yet nothing reveals better the "tonality" of Great Lent in the Orthodox Church; nowhere is better manifested its profound appeal to man.
The service begins as solemn Vespers with clergy in bright vestments. The hymns (stichira) which follow the Psalm "Lord, I have cried..." announce the coming of Lent and, beyond Lent, the approach of Pascha!
Let us begin the time of fasting in light!
Preparing ourselves for the spiritual efforts.
Let us purify our soul; let us purify our body.
As from food, let us abstain from all passion
And enjoy the virtues of the spirit,
So that perfected in time by love
We may all be made worthy to see
The Passion of Christ and the Holy Pascha
In spiritual joy!
Then comes, as usual, the Entrance with the evening hymn: "O Gladsome radiance of the holy glory...." The celebrant then proceeds to the "high place" behind the altar for the proclamation of the evening Prokeimenon which always announces the end of one and the beginning of another day. This day's Great Prokeimenon announces thus the beginning of Lent:
Turn not away Thy face from Thy servant for I am afflicted!
Hear me speedily.
Attend to my soul and deliver it!
Listen to the unique melody of this verse-- to this cry that suddenly fills the church: "...for I am afflicted!"-- and you will understand this starting point of Lent: the mysterious mixture of despair and hope, of darkness and light. All preparation has now come to an end. I stand before God, before the glory and the beauty of His Kingdom. I realize that I belong to it, that I have no other home, no other joy, no other goal; I also realize that I am exiled from it into the darkness and sadness of sin, "for I am afflicted!" And finally, I realize that only God can help in that affliction, that only He can "attend to my soul." Repentance is, above everything else, a desperate call for that divine help.
Five times we repeat the Prokeimenon. And then, Lent is here! Bright vestments are put aside; lights are extinguished. When the celebrant intones the petitions for the evening litany, the choir responds in the lenten "key." For the first time the lenten prayer of St. Ephraim accompanied by prostrations is read. At the end of the service all the faithful approach the priest and one another asking for mutual forgiveness. But as they perform this rite of reconciliation, as Lent is inaugurated by this movement of love, reunion and brotherhood, the choir sings the Paschal hymns. We will have to wander forty days through the desert of Lent. Yet at the end shines already the light of Easter, the light of the Kingdom.