The Divine Liturgy has its origins in the Sacrament of the Holy Eucharist, instituted by the Lord Himself: Now on the first day of Unleavened Bread the disciples came to Jesus, saying, Where will You have us prepare for You to eat the passover? He said, Go into the city to a certain one, and 'say to him, 'The Teacher says, My time is at hand; I will keep the Passover at your house with My disciples.' And the disciples did as Jesus had directed them, and they prepared the Passover. When it was evening, He sat at table with the twelve disciples.... Now as they were eating, Jesus took bread, and blessed, and broke it, and gave it to the disciples and said, Take, eat; this is My body. And He took a cup, and when He had given thanks He gave it to them, saying, Drink of it, all of you; for this is My blood of the new covenant, which is poured out for many for the forgiveness of sins... And when they had sung a hymn, they went out to the Mount of Olives (Matt. 26:17-20; 26-28, 30). This Eucharistic Supper and the Lord's commandments concerning it were held sacred by the Apostles; for when they met together, they spent the time in prayer, in the singing of sacred hymns, and the breaking of bread in memory of Christ. That is, they celebrated the Holy Eucharist. This custom became the cornerstone of the new Christian community, and is witnessed to by St. Paul in his first letter to the Corinthians: / received from the Lord what I also delivered to you, that the Lord Jesus on the night when He was betrayed took bread, and when He had given thanks, He broke it, and said, This is My body which is broken for you. Do this in remembrance of Me. In the same way also the cup, after supper, saying, This cup is the new covenant in My blood. Do this, as often as you drink it, in remembrance of Me (1 Cor. 11:23-25).
In the course of time the Eucharistic gathering became more developed. Originally the public portion of the Liturgy (the Synaxis, or gathering), consisting of instruction, Scripture readings, etc., primarily for the Catechumens who were about to receive Baptism, and the Eucharist (a private gathering of the faithful only) were celebrated separately; but about the 4th Century they were linked together, and eventually expanded. In time, the Service of Preparation (or Proskomedia) was joined to it.
Customarily three Liturgies are celebrated by the Orthodox the Liturgy of St. John Chrysostom, the Liturgy of St. Basil the Great, and the Liturgy of the Presanctified Gifts. The first two are entitled ...of Saint John..., ...of St. Basil..., since each contains prayers undoubtedly composed by St. John and St. Basil, respectively. The Presanctified Liturgy (at which no consecration takes place, since the Holy Gifts are presanctified on the previous Sunday) probably contains prayers composed by Pope St. Gregory Dialoges, to whom this Liturgy is attributed. In addition, in a few places, such as at Jerusalem, the Liturgy of St. James the Brother of the Lord is celebrated only on the patronal feast day of St. James (Oct. 23).
The Divine Liturgy can be celebrated only by a Bishop or a Priest, and neither can celebrate more than one Liturgy in one day. This is because they must partake of the Holy Gifts, having, of necessity, prepared themselves beforehand by fasting, prayer, etc. [If the Holy Gifts would be consumed before another Liturgy, the fast would therefore be broken!] The Liturgy can be celebrated only at an Altar (Holy Table) upon which is placed an Antimension consecrated by a Bishop this constitutes his permission to serve the Liturgy although the Liturgy may be served at another place, as long as the Antimension is present. Not more than one Liturgy may be celebrated at one Altar (Holy Table), upon one Antimension, in one day.
Upon entering the church before the Divine Liturgy is to be served, the Priest (and Deacon) stand before the Holy Doors and say the Entrance Prayers. Then, after asking for and receiving in turn forgiveness of the faithful, they enter the Altar; and having made three prostrations before the Holy Table, they kiss the Holy Gospel (Priest) and the Table itself (Priest and Deacon). After this they vest with appropriate prayers and blessings the Deacon in Stikharion, Cuffs and Orarion (Stole), and the Priest in Cassock, Epitrachelion, Belt, Cuffs, Nabedrennik and Palitsa (if so awarded), as well as the Phelonion. Then both wash their hands and prepare to celebrate the Liturgy of Preparation (the Proskomedia).