Liturgy of Preparation
The Liturgy of Preparation, also Prothesis (Greek Προθησις a setting forth) or Proskomedia (an offering), is the name given in the Eastern Orthodox Church and the Byzantine-rite Eastern Catholic Churches to the act of preparing the bread and wine for the Eucharist. The Liturgy of Preparation is done quietly before the public part of the Divine Liturgy begins, and symbolizes the "hidden years" of Christ's earthly life.
 Eucharistic Elements
Only very specific elements may be offered at the Divine Liturgy:
The bread used for the Liturgy is referred to as prosphora. A prosphoron is a round loaf of leavened bread baked in two layers to represent the two natures of Christ. It has a square seal on the top side which has inscribed on it a cross and the Greek letters IC (an abbreviation in Greek for "Jesus") XC ("Christ") and NIKA ("Conquers"). The portion of the loaf that is cut out along this seal is the Lamb (Host), from which all are communicated, and therefore must be proportionately large for the number of communicants.
Prosphora must be made using only the finest wheat flour, water, salt, and yeast. It should be freshly baked and without blemish.
The Greeks will use one large loaf for the Liturgy of Preparation, with a large round seal on it inscribed not only with the square seal mentioned above (from which the Lamb will be taken), but also markings indicating where the portions for the Theotokos, the Ranks, the Living and Dead will be removed (see Proskomedie, below).
Those churches which follow Slavic usage will use five small loaves, recalling the five loaves from which Christ fed the multitude (John 6:5-14). Normally all will be stamped with a small square seal, though special seals for the Theotokos are sometimes used.
In all traditions, only the Lamb is actually consecrated, other portions which are removed from the prosphora are memorials, but are never to be used for Communion.
The Wine used must be red grape wine, and it must be fermented. Orthodox tend to favor altar wine that is somewhat sweet, though this is not a requirement.
These elements are referred to collectively as the "Gifts", both before and after the Consecration.
The Priest's Service Book states that, before celebrating the Divine Liturgy, the priest must be reconciled to all men, keep his heart from evil thoughts, and be fasting since midnight. The same rules apply to the deacon.
The clergy who will be celebrating the Liturgy (the priests and deacons) stand together in front of the Holy Doors of the Iconostasis, venerate the icons, and say special Entrance Prayers before they enter into the Altar. At the end of these prayers, they will bow to the throne of the bishop who oversees the church, or, if it is a monastery, the Hegumen, acknowledging the authority of their spiritual superiors, without whose permission they may not celebrate the Divine Services.
They then venerate the Holy Table and put on their vestments. Before putting on each vestment the priest will say a prayer, usually drawn from the Psalms, bless the vestment, and kiss the cross that is sewn onto it. The deacon will bring his vestments to the priest for him to bless. He then kisses the priest's hand and withdraws to vest, saying the same prayers as the priest and kissing the cross on each vestment. Any servers who will be vesting must bring their sticharia to the priest for him to bless, before vesting. Though servers do not normally say the prayer of the sticharion, they will kiss the cross before vesting. If a bishop is present in the Altar, the clergy will bring their vestments for him to bless before putting them on.
After vesting, the priest and deacon wash their hands, saying the Prayer of the Washing of Hands (Psalm 35:6-12) They then go to the Prothesis (Table of Oblation) where the Gifts are to be prepared.
If there are several priests concelebrating, usually only one—traditionally, the most junior—will celebrate the Proskomedia. Others may assist in taking out particles for the living and the dead.
 The Lamb
The priest takes a prosphoron and blessed it three times, making the sign of the cross over it with the liturgical spear. Then, cutting on all four sides of the square seal on the prosphoron, he removes a cube (the Lamb), taking from both layers of the loaf, and places it in the center of the diskos. He then cuts the underside of the Lamb, making a cross, then turns the Lamb right side up and pierces it with the spear, saying the words from the Gospel (John 19:34-35). (See Lamb for more details).
The deacon mingles a little water with the wine that will be poured in the chalice and presents it to the priest for him to bless. The deacon then pours the wine and water into the chalice, as the priest says, "Blessed be the union of Thy holy things, now and ever, and unto the ages of ages. Amen."
 The Theotokos
Next the priest takes up the second prosphoron, blesses it with the spear, and cuts a large, triangular particle from it, which he places on the diskos next to the Lamb in commemoration of the Theotokos. This loaf (if it is a separate loaf) will sometimes have been sealed with an icon of the Mother of God, or with her monogram.
 The ranks
Next, the priest takes up the prosphoron of the Nine Ranks. From this loaf will be taken smaller triangular particles in commemoration of the various ranks of saints. There are some differences between the Greek and the Slavic texts as to which particular saints are named, but the intent is that all of the saints are included. Saint John the Forerunner and the Patron Saint of the church or monastery are always named. The number nine was chosen because that is the traditional number of the ranks of angels.
These nine particles are placed to the left of the Lamb (i.e., to the priest's right, as he looks down on the diskos).
 The living
Then the priest takes up the prosphoron for the Living. He will take out a larger particle in commemoration of the Patriarch (or Synod of Bishops), and a second larger particle in commemoration of the Ruler (in former times, this would have been the Emperor, but nowadays it reflects the government of the local nation in which the church is located). He then takes out smaller particles in commemoration of others among the living. He must always commemorate the Bishop who ordained him (if he is still among the living), the clergy who are concelebrating with him, and any living Orthodox Christian whom he wishes. Churches and monasteries will often have diptychs (memorial books) of the living and departed who should be commemorated at every Liturgy.
Among the Slavic peoples, it is customary for the laity to offer small prosphora in commemoration of those living and the departed whom they would like to have prayed for during the Liturgy. These will often be smaller than the five prosphora used by the priest. They will hand these to the priest together with their list of names, and he will take particles out (living from the top of the loaf, departed from the bottom) and place them on the diskos. The loaves will be returned to the faithful.
All of the particles for the living are placed in a line below the Lamb and the particles for the Theotokos and saints.
 The departed
From the prosphoron of the Departed the priest will take a larger particle as a general memorial of the departed hierarchs, rulers and the founders of the local church or monastery. He then takes out smaller particles in commemoration of departed Orthodox Christians. He will commemorate the Bishop who ordained him (if he is departed) and any of the departed whom he will, as well as the names in the diptychs and those presented by the faithful.
All of the particles for the departed are placed in a line below the particles for the living.
Before the conclusion, any concelebrating priests who would like to make their own commemorations of the living and the departed may do so.
 The celebrant himself
For the last commemoration, the priest takes out a particle for himself, saying: "Remember, O Lord, mine unworthy self, and pardon me every transgression, whether voluntary or involuntary."
The deacon places incense in the censer and holds it up for the priest to bless. The priest blesses the incense saying the Prayer of the Censer. Next, the priest takes the Asterisk (star cover), holds it over the censer and then places it on the diskos, saying: "And the star came and stood over the place where the young child was."
He then holds each of the smaller veils over the censer and places them on the discos and the chalice, respectively, saying appropriate prayers for each.
Then he takes the larger veil, called the Aër, wraps it around the censer and then covers the chalice and diskos together.
Afterwards, the deacon will perform a full censing of the Prothesis, the Holy Table, the sanctuary, the entire church and the people while he recites the following hymn and Psalm 50 quietly to himself:
In the Tomb with the body, and in Hades with the soul, in Paradise with the thief, and on the Throne with the Father and the Spirit, wast thou, O Christ, who art everywhere present and fillest all things.
 Hierarchical Liturgy
When a bishop is serving the Divine Liturgy, one of the priests will vest and perform the Liturgy of Preparation as normal, except that will not commemorate the other clergy who are serving; nor will he say the Prayer of Oblation, and there will be no censing of the temple at its conclusion. Also, the reading of the Hours will not begin until after the arrival of the bishop. The Proskomedie must be finished before the arrival of the bishop.
When it is time, the bishop enters formally into the church and the deacon reads the Entrance Prayers for him and he is then vested by the subdeacons while the deacon reads the Vesting Prayers for him. Then the Reader begins the Little Hours. After the Liturgy begins, the Bishop himself will say the Prayer of Oblation.
Just before the Great Entrance, the bishop himself will commemorate anyone of the living and the dead whom he wishes, taking out particles from a special prosphoron that has been prepared for him. Then each priest, deacon and server will come to the bishop and ask him to pray for him, kissing the bishop's shoulder, and the bishop will take out a particle for him, commemorating him by name.
 Great Lent
During Great Lent it is not permitted to celebrate the Divine Liturgy on weekdays. However, on Wednesdays and Fridays the faithful may receive Holy Communion from the reserved Mysteries (Sacrament) at the Liturgy of the Presanctified Gifts. In order to provide for these services, on the Sunday before, the priest must cut out two extra Lambs (one for Wednesday, and one for Friday), or however many Presanctified Liturgies there will be that week.
During Bright Week (The week following Easter Sunday) most of the services are quite radically different than during the rest of the year. However, at the Liturgy of Preparation, only the Entrance Prayers change; everything else remains the same.
 Oriental Orthodox
The various Oriental Orthodox Churches also have Liturgies of Preparation before the commencement of the public portion of the Divine Liturgy. `Some of these are very simple, and some are more complex. They all involve the entry of the clergy, vesting and preparing the Gifts of bread and wine, accompanied by appropriate prayers.
- Among Eastern Christians, the entire sanctuary may be referred to as the "Altar"; the Altar Table itself being referred to as either the "Holy Table" or the "Throne."
- This commemorates the fact that, when the soldiers pierced Christs' side with a spear, blood and water came forth.
- The Greeks will perform all of the same actions as the Russians, but they use only one loaf, removing all particles from the same loaf. The instructions here will presume the celebrant is using five loaves.
- The particle for the Theotokos is placed to the Lamb's right (i.e., the celebrant's left, in remembrance of the Psalm vere, "The queen stood at the King's right hand."(Psalm 44:8).
- See F. E. Brightman (1896), Liturgies Eastern and Western
- Any other priests who will be concelebrating will not say their vesting prayers until after the arrival of the bishop.
- This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press.
- This article incorporates text from a publication now in the public domain: Chambers, Ephraim, ed. (1728). "article name needed". Cyclopaedia, or an Universal Dictionary of Arts and Sciences (first ed.). James and John Knapton, et al.