Originally in the East, people deposited their offerings of bread and wine at the front of the church on their way inside. In the Hagia Sophia, the Imperial church of Constantinople, these gifts were prepared by the deacons in a small round building called the skevophylakion at the north-east corner of the church. The deacons initially did everything: they received the gifts, sorted them, prepared them, finally bringing them into the church and up to the altar at the Great Entrance. The performance of the Proskomide by the deacon -- and not the priest -- was continued until the fourteenth century. The preparation of the gifts became a full blown rite around the time of Saint Maximus the Confessor in the early seventh century. By the time of Saint Germanus in the eighth century, the Proskomide had acquired a definite symbolic significance.

The reason for offering the gifts during the Proskomide is to give thanks to God and to make supplication to Him. The Proskomide service is ministered on the Prothesis, a table built into the wall of the apse. The Prothesis is situated on the left side as one faces the Iconostasis from the nave. The apse of the Prothesis symbolizes the manger.

The bread which is to be changed into Christ’s Body is separated from the rest of the loaves by the priest, who places it on the holy Diskos (paten) and consecrates it (sets it apart) to God. He then carries it to the altar and offers it up. This round loaf of bread, which is made of pure wheat, is called the prosphora (the “offering” or “gift”) and is stamped on the top with a special seal (called the Sphragis or Panagiari). The bread must also be leavened, leaven symbolizing our participation in the person of Jesus Christ, the Word of God who became man. The Orthodox also see leaven as manifesting the Church as the Body of Christ, which only exists insofar as it participates in the leavened eucharistic Body of Christ. This recalls what Jesus said: “The kingdom of heaven is like leaven.”43 The Orthodox Church tends to see unleavened bread as a symbolic relapsing into the Old Covenant, denying the Incarnation and consequently the salvific grace of the Gospel.

The Prothesis signifies the place of Calvary, where Jesus was “offered up” to God. Calvary was prefigured in the Old Testament by Abraham when God commanded him to make an altar of stone on a mountain, collect wood, and sacrifice his son on it. In his mercy, though, God allowed a ram to be offered instead. This was to show that the Father was pleased to allow, in “the fullness of time,” His eternal Son to be incarnate of the pure virgin Theotokos and to be sacrificed for our sins. Though in His Divinity He remained impassible (not subject to pain), nevertheless, as a man Christ suffered all His torments to the fullest -- and gladly because of His immense love for us.

Two basic sacred accessories are used during the Divine Liturgy: The Chalice or Holy Cup and the Paten or Holy Diskos. Into the Chalice the priest pours the offered wine, whereas on the Diskos he places the offered bread. It is Christ himself who named His Sacrifice by crucifixion 'a cup' that His Father has given Him. But the moment the Lord was crucified, this cup of death became a 'cup of blessing', a cup of the salvation of humankind. ' The Discos on which the bread is placed, according to the eighth century Patriarch of Constantinople, Saint Germanus, “represents the hands of Joseph of Arimathea and Nicodemus, who buried Christ. The Discos on which Christ is carried is also interpreted as the sphere of heaven, manifesting to us in miniature the spiritual sun, Christ, and containing Him visibly in the bread. The Chalice corresponds to the vessel which received the mixture [of water and blood] which poured from the bloodied, undefiled side and from the hands and feet of Christ. Or again, the Chalice corresponds to the bowl which the Lord depicts, that is, Wisdom; because the Son of God has mixed His blood for drinking instead of wine, and set forth on His holy table, saying to all: `Drink of my blood mixed for you for the remission of sins and eternal life.’ The cover on the Discos represents the cloth which covered Christ's face in the tomb. The veil, or the aer, is a rectangular ornamented veil for covering both the Chalice and Diskos after the Proskomide. The aer corresponds to the stone which Joseph placed over the entrance of the tomb and which Pilate’s guards then sealed. It can also represent the shroud which contained the Lord’s body.

After having prostrated three times in a row, the priest asks God's mercy so as to proceed with the preparation of the gifts for the Eucharist. He elevates to the level of his head one of the prosphora together with the Lance, while with his words he underlines the fact that Christ was crucified and he was 'pierced' with a spear so as to redeem humans from the 'old law', i.e. from being slaves to the religious provisions of the Law of Moses, and to save them from sin and death.  This small metal knife which is designed to look like a spear was probably introduced sometime around the ninth century. Holding the loaf in his left hand and the spear in his right, the priest makes the sign of the cross with the spear three times over the loaf, saying each time: “In remembrance of our Lord and God and Savior Jesus Christ.” The priest thus recalls the Lord’s command, “Do this in remembrance of me.” This command applies not only to the gifts being consecrated, but to the Liturgy as a whole. We are to “do” the Liturgy “in remembrance” of all that Christ did to achieve our salvation, even those events (indeed, especially those events!) which seem to denote nothing but weakness: His Cross, His Passion, and His Death.

Immediately after that, the priest makes the sign of the cross over the prosphoron, the central part of which—the Lamb or Amnos—he will remove shortly afterwards so as to be consecrated, with the invocation of the Holy Spirit, into the Body of Christ. The Lamb, situated in the center of the bread, is the square section were the “seal” is stamped onto the prosphora. It is known as the “Lamb” because it is the part which shall be changed into the Body of Christ. On the Lamb is written “IC XC NIKA,” which is a Greek abbreviation meaning, “Jesus Christ Conquers.” This strange paradox of the “Lamb” which “conquers” recalls the vision of John in the Book of Revelation, where those who follow the beast “make war with the Lamb, and the Lamb will overcome them, for He is Lord of lords and King of kings; and those who are with Him are called chosen, and faithful”. This underlines the fact that in every part of the Diving Liturgy there is a 'remembrance' of Christ. Actually it is Christ himself who instructed His disciples to celebrate the Divine Liturgy 'in remembrance' of Him. Thus the Divine Liturgy is the act by which Christ's presence among us is manifested.

This remembrance is not void of content: Taking the spear and cutting along the right edge of the Lamb (on the priest's left), the priest says, echoing the prophecy in Isaiah: “Like the Lamb that is led to the slaughter.” The lamb normally symbolizes, among other things, helplessness, innocence and gentleness. When the image of a lamb is used figuratively of a person, it arouses sympathy, concern, pity and compassion for that person. In the Old Testament, the lamb is a symbol of Israel and the Lord is called their Shepherd, as in Psalm 23. The lamb is also the sacrificial victim brought as an offering to God for the salvation of the Chosen People, and the blood of these offerings was used to cleanse the sanctuary in the Temple. In the Old Testament the sacrifice of a lamb is at the heart of the most important Jewish feast of all, the Passover. Indeed, all the major feasts of the Israelites call for the sacrifice of a lamb. The above act is also an image of the Lord leaving this world and going to the Father through death: 'again, I am leaving the world and am going to the Father' (John 16:28).

Cutting along the left edge of the Lamb, the priest says, citing Isaiah 53:7 from the Greek Septuagint: “And like a blameless sheep that before its shearer is silent, so He did not open His mouth.” Cutting along the upper edge of the Lamb, the priest cites the next verse in Isaiah: “In His humiliation right judgment was denied Him.”

Cutting along the lower edge of the Lamb, the priest continues reciting Isaiah 53:8: “Who could have told His posterity?”  This cutting of the loaf is done for practical reasons, so that the Host may be removed. It has a symbolic value also -- it represents our Lord's passing from the world to His Father, as He Himself said, “I leave the world, and go to the Father.”

Piercing the bread at the right corner of the seal and cutting away the bottom crust, the priest removes the Lamb from the loaf and finishes citing Isaiah 53:8: “For His life is taken up from the earth.”

Then the priest proceeds with a symbolic representation of the Crucifixion: he places the Amnos on the Diskos announcing Christ's Sacrifice. He seals, i.e. he makes a deep crosswise cut in the Amnos, without cutting through it, commemorating the benefactions of the Lord's Sacrifice by Crucifixion. As he does this, the priest repeats the words of John the Baptist: “The Lamb of God, who takes away the sin of the world,55 is sacrificed for the life of the world and its salvation.” The aforementioned gifts, especially the Amnos, are offered both in thanksgiving for all benefactions we are already given and in supplication for all benefactions to come. Thus, the central part is separated from the rest of the prosphoron so as to be dedicated to God and consecrated. This reminds us of the fact that the Lord was separated from humans—in whose nature He partakes out of loving kindness—so as to be led as the sheep to the slaughter. Not yet distancing himself from what happened at the Crucifixion, the priest commemorates the spearing of the Lord's side from where came out blood and water: 'one of the soldiers pierced His side with a spear, and at once blood and water came out'. In the same way the priest pierces the central part of the Lamb and simultaneously pours a portion of nama and water into the Chalice. He then blesses the union of the two elements in the Chalice.

Afterwards, the priest starts cutting out portions of the prosphoron in memory of the Mother of God, of the Saints, etc. It should be noted that, while still performing the Kairos office, the priest asks the Virgin Mary to intercede with God so that he may be worthy to celebrate the Divine Liturgy. The Mother of God is in reality a bond between Heaven and Earth. Her pre-eminence is underlined by the placing of her portion—a triangular one marked with the letters Μ and Θ (i.e. Μother of God [in Greek Μήτηρ Θεοῦ]—in the right of the Amnos, i.e. in the side of Christ. And this is expressed in such terms as 'at your right hand stands the Queen (...)'

Then the priest lifts out a portion in memory of the Angels and places it in the left of the Lamb. Next in importance, after the Mother of God, come the Angels, who also acted as servants to God insofar as His plan of human salvation is concerned. The place next to Christ (the Amnos) is rightfully theirs, in any case they are going to be invisibly present during the celebration of the Divine Liturgy.

At the side of—and under—the Angels' portion the priest places three groups of similar portions, in three columns, to commemorate: St John the Baptist; the Prophets; the praiseworthy Apostles; the Great Fathers, Teachers and Hierarchs of the Church; Stephen the Protomartyr; the Martyrs; the Holy Ascetics of the Church; the Holy Unmercenaries; the Ancestors; the Saint of the day; and St John Chrysostom, the author of the Divine Liturgy. This configuration of Saints around Christ has a deeper meaning: it indicates not only that when the Church celebrates the Divine Liturgy there is a great unity between the faithful and the Saints, but also that the Saints are considered by the Church as paragons of righteous life. Leading such a life they obtained a place beside Christ and became 'the assembly of the firstborn who are enrolled in Heaven' (Hebrews 12:23).

Next in order is the commemoration of the living—those who press on toward the goal for the prize of the heavenly call of God—and of the departed. First there is a commemoration of all the Orthodox Churches and secondly a commemoration of the Bishop of the local Church. Portions of the prosphoron for all the aforementioned people are placed below the Amnos. Then the priest mentions by name several living and departed people cutting very small pieces—a particle for each one of them—out of the prosphoron and placing them below the Amnos. Finally, the priest mentions his own name, asking God to forgive all his sins so as to able to officiate. The Office of Preparation ends here, on the Diskos lies a summary of the perfect form of the Church, this 'body' of universal dimensions, extending over both the heavens and the Earth and encompassing not only the living but also the departed. The Church is the living image of the Body of Christ! A complete society in a complete body, according to Paul Evdokimov.

The priest then kisses the spear and puts it aside. Next, the priest blesses the censer, saying: “Blessed is our God, always, now and ever, and to the ages of ages. Incense we offer to You, O Christ our God, as a fragrant spiritual offering which You receive upon Your most heavenly altar and send down upon us in return the grace of Your all-holy Spirit.”