Central to our lives as Orthodox Christians are the Cycle of Services. Through the services and the Sacraments administered in and through them, we are healed and filled with the Grace of The Holy Spirit.
A normal weekly cycle involves Great Vespers on Saturday evening, Orthros or Matins and the Divine Liturgy on Sunday morning. Other services are prescribed throughout the year, but these services are the backbone and foundation of the Orthodox worship experience.
Vespers, or Great Vespers if it is sung on Saturday, is the beginning of the weekend liturgical cycle. In a somewhat contradictory sense, Vespers is the first service of the Sunday Cycle, since we celebrate Vespers at the "setting of the sun". In Orthodox practice, when the prokeimenon is sung, the next day has begun.
The Vespers service is meant to remind us of the Old Testament period, the creation of the world, the first human beings fall into sin, of their expulsion from Paradise, their repentance and prayer for salvation, the hope of mankind in accordance with the promise of God for a Saviour and ending with the fulfillment of that promise.
Meaning "early dawn" or "daybreak" Orthros is celebrated immediately preceding the Divine Liturgy. Comprised of petitions, readings of the Psalms and hymns it is can be thought of as the "beginning" prayers of the Divine Liturgy.
The Divine Liturgy
The Divine Liturgy is the primary worship service of the Church. The most commonly celebrated forms of the Divine Liturgy are the Liturgy of St. John Chrysostom, the Liturgy of St. Basil, and the Liturgy of the Presanctified Gifts.
The Divine Liturgy is a eucharistic service. It contains two parts: the Liturgy of the Catechumens, sometimes called the Liturgy of the Word, at which the Scriptures are proclaimed and expounded; and the Liturgy of the Faithful, sometimes called the Liturgy of the Eucharist, in which the gifts of bread and wine are offered and consecrated.
The Church teaches that the gifts truly become the body and blood of Jesus Christ, but it has never dogmatized a particular formula for describing this transformation. The Prothesis (or Proskomedia), the service of preparing the holy gifts, can be considered a third part which precedes the Liturgy proper.
Within the Divine Liturgy we pray for ourselves and our world, we are bathed in scripture and partake of the Body and Blood of our Risen Savior.