Communion, the Lord's Supper, or the Eucharist: whatever you call it, there's a relatively consistent tradition on its meaning and practice in these quotes from throughout Christian history.
The word Eucharist means "thanksgiving," and it is what the early church commonly called the fellowship meal of bread and wine. The word communion comes from 1 Cor. 10:16, where the Greek word is koinonia, which would be better translated "fellowship" today. The verse says:
The cup of blessing which we bless, is it not the fellowship of the blood of Christ? The bread which we break, is it not the fellowship of the body of Christ?
In context, the word "fellowship" here can also mean having a part in or partaking of the blood and body of Christ.
Finally, the term, "the Lord's supper," is used in 1 Cor. 11:20 to refer to the fellowship meal. Eucharisteo—Eucharist or thanksgiving—is used in that passage as well, in v. 24.
Rainbow over Jackson, Tn
Break one and the same bread, which is the medicine of immortality, the antidote which prevents us from dying, and a cleansing remedy driving away evil so that we should live in God through Jesus Christ. (Letter to the Ephesians 20)
Clothe yourselves with meekness and be renewed in faith—that is, the flesh of the Lord—and in love—that is, the blood of Jesus Christ. (Letter to the Trallians 8)
Take heed ... to have but one Eucharist. For there is one flesh of our Lord Jesus Christ and one cup to show forth the unity of his blood; one altar, as there is one bishop, along with the elders and deacons, my fellow-servants. (Letter to the Philadelphians 4)
[The gnostics] abstain from the Eucharist and from prayer because they do not confess the Eucharist to be the flesh of our Savior Jesus Christ, who suffered for our sins and which the Father, out of his goodness, raised up again. Those, therefore, who speak against the gift of God, incur death in the midst of their disputes. It would be better for them to treat it with respect so that they, too, might rise again. It is appropriate, therefore, that you keep aloof from people like them and avoid speaking with them either privately or publicly. Instead, pay attention to the prophets and, above all, to the Gospel, in which the suffering of Christ has been revealed to us and the resurrection has been fully proven. (Letter to the Smyrneans 7)
I need to point out here that the denial of the resurrection by the gnostics is at the heart of this quote by Ignatius [from Smyrneans 7]. They deny that the Eucharist is the body of Christ because they deny that Christ rose again. They were opposed to flesh and material creation in every way.
Thus, we are told to avoid people like them not only because they denied that the Eucharist was the body of Christ, but also because they denied the resurrection.
Let that be deemed a proper Eucharist which is by the bishop or by one to whom he has entrusted it. Wherever the bishop shall appear, let the multitude of also be, just as wherever Jesus Christ is, there is the catholic [i.e., universal] church. It is not lawful either to baptize or to celebrate a love feast without the bishop, but whatever he approves of, that is also pleasing to God. (Letter to the Smyrneans 8)
There is then brought to the president of the brethren [I think this refers to whoever is presiding at a meeting, but no one knows for certain] bread and a cup of wine mixed with water. He takes them, gives praise and glory to the Father of the universe through the name of the Son and of the Holy Spirit, and offers thanks at considerable length for our being counted worthy to receive these things at his hands. And when he has concluded the prayers and thanksgivings, all the people present express their assent by saying Amen. …
And when the president has given thanks, and all the people have expressed their assent, those who are called by us deacons give to each of those present to partake of the bread and wine mixed with water over which the thanksgiving was pronounced, and to those who are absent they carry away a portion. (First Apology 65)
Justin Martyr and Tertullian both refer to "the president" leading a service, and they do this 50 years apart.
While no one can know for certain to whom they're referring, most likely they are simply calling whoever was leading that particular service "the presiding one." Shortly after Tertullian's time, Hippolytus, in his Apostolic Traditions, says that meetings which include communion should be led by the bishop, the elders, or a representative they've chosen.
Was that true in Justin's day? Or Tertullian's? Possibly, and possibly not. Either way, the most likely interpretation is that they used "president" because it wouldn't necessarily be a bishop or an elder that was leading the communion meeting.
And this food is called among us the Eucharist, of which no one is allowed to partake but the man who believes that the things which we teach are true, who has been washed with the washing that is for the remission of sins and to regeneration, and who is so living as Christ has enjoined. For not as common bread and common drink do we receive these, but in the same way as Jesus Christ our Savior, having been made flesh by the Word of God, had both flesh and blood for our salvation, so likewise have we been taught that the food which is blessed by the prayer of his word, and from which our blood and flesh by transmutation are nourished, is the flesh and blood of that Jesus who was made flesh.
For the apostles, in the memoirs composed by them, which are called Gospels, have thus delivered to us what was commanded to them, that Jesus took bread, and when he had given thanks, said, "This do in remembrance of me, this is my body." In the same way, having taken the cup and given thanks, he said, "This is my blood," and he gave it to them alone.
This the wicked devils have imitated in the mysteries of Mithras, commanding the same thing to be done. For, that bread and a cup of water are placed with certain incantations in the mystic rites of one who is being initiated, you either know or can learn. (First Apology 66)
"The offering of fine flour, sirs," I said, "which was prescribed to be presented on behalf of those purified from leprosy, was a type of the bread of the Eucharist [i.e., communion or Lord's supper; Eucharist means "thanksgiving"]. Our Lord Jesus Christ prescribed this celebration in memory of the suffering which he endured on behalf of those who are purified in soul from all iniquity, in order that we may … thank [reference to Eucharist, meaning thanksgiving] God for having created the world … for the sake of man, for delivering us from the evil we were in, and for utterly overthrowing principalities and powers by him who suffered according to his will." (Dialogue with Trypho 41)
God speaks by the mouth of Malachi ... about the sacrifices presented by you [Jews] at that time: "'I have no pleasure in you,' says the Lord, "and I will not accept sacrifices at your hands ... my name has been glorified among the Gentiles, and in every place incense is offered to my name and a pure offering. For my name is great among the Gentiles," says the Lord, "but you profane it" (Mal. 1:10-12).
He, then, speaks of those Gentiles—namely us [Christians]—who offer sacrifices to him in every place; in other words, the bread of the Eucharist and also the cup of the Eucharist, affirming both that we glorify his name and that you profane it. (Dialogue with Trypho 41, emphasis mine)
How can [the gnostics] be consistent with themselves , that the bread over which thanks have been given is the body of their Lord, and the cup his blood, if they do not call him the Son of the Creator of the world, that is, his Word? ... Then, again, how can they say that the flesh, which is nourished with the body of the Lord and with his blood, goes to corruption but does not partake of life?
... Our opinion is in accordance with the Eucharist, and the Eucharist in turn establishes our opinion. We offer to him his own, announcing consistently the fellowship and union of the flesh and spirit. For as the bread, which is produced from the earth, when it receives the invocation of God, is no longer common bread, but the Eucharist, consisting of two realities, earthly and heavenly. So also our bodies, when they receive the Eucharist, are no longer corruptible, having the hope of resurrection to eternity.
Now we make offering to him, not as though he stood in need of it, but rendering thanks for his gift, and thus sanctifying what has been created. For even as God does not need our possessions, so do we need to offer something to God. As Solomon says, "He that has pity on the poor lends to the Lord" [Pr. 19:17]. (Against Heresies IV:18:4-6)
But vain in every respect are they who despise the entire dispensation of God, disallow the salvation of the flesh, and treat with contempt its regeneration, maintaining that it is not capable of imperishability. But if [the flesh] does not really attain salvation, then neither did the Lord redeem us with his blood, nor is the cup of the Eucharist the fellowship of his blood, nor the bread which we break the fellowship of his body.
For blood can only come from veins and flesh and whatever else makes up the substance of man, such as the Word of God was actually made. By his own blood he redeemed us ...
And as we are His members, we are also nourished by means of the creation ... He has acknowledged the cup as his own blood, from which he bedews our blood; and he has established the bread as his own body, from which he gives increase to our bodies.
When, therefore, the mingled cup and the manufactured bread receives the Word of God and the Eucharist [literally, "Thanksgiving"] of the blood and the body of Christ is made, from which things the substance of our flesh is increased and supported, how can they affirm that the flesh is incapable of receiving the gift of God, which is life eternal, when that flesh is nourished from the body and blood of the Lord and is a member of Him?
The blessed Paul declares in his letter to the Ephesians that "we are members of his body, of his flesh, and of his bones" [Eph. 5:30]. He does not speak these words of some spiritual and invisible man, for a spirit does not have bones or flesh, but of that dispensation of an actual man, consisting of flesh, nerves, and bones—that same flesh which is nourished by the cup which is his blood and receives increase from the bread which is his body.
And just as a cutting from the vine planted in the ground comes to fruit in its season, or as a corn of wheat falling into the earth and becoming decomposed, rises with manifold increase by the Spirit of God ... and then, through the wisdom of God, serves for the use of men, and having received the Word of God, becomes the Eucharist, which is the body and blood of Christ; so also our bodies, being nourished by it, deposited in the earth, and suffering decomposition there, shall rise at their appointed time, the Word of God granting them resurrection to the glory of God, even the Father, who freely gives to this mortal immortality, and to this corruptible incorruptibility. (Against Heresies V:II)
Here is to be noted the mystery of the bread, inasmuch as he speaks of it as flesh; and as flesh that has risen through fire, as the wheat springs up from decay and germination. In truth, it has risen through fire for the joy of the Church, as bread baked. … But since He said, "And the bread which I will give is My flesh," and since flesh is moistened with blood, and blood is figuratively termed wine, we are bidden to know that, as bread, crumbled into a mixture of wine and water, seizes on the wine and leaves the watery portion, so also the flesh of Christ, the bread of heaven absorbs the blood; that is, those among men who are heavenly, nourishing them up to immortality, and leaving only to destruction the lusts of the flesh. (The Instructor I:7)
Furthermore, milk is mixed with sweet wine; and the mixture is beneficial, as when suffering is mixed in the cup in order to immortality. For the milk is curdled by the wine, and separated, and whatever adulteration is in it is drained off. (The Instructor I:7)
Afterwards [after the Israelites arrived in Canaan, after drinking water in the wilderness] the sacred vine produced the prophetic cluster. This was a sign to them, when wandering had trained them, and they entered their rest. It represents the great cluster, the Word, bruised for us. For the blood of the grape—that is, the Word—desired to be mixed with water, as his blood is mingled with salvation.
And the blood of the Lord is twofold. For there is the blood of his flesh, by which we are redeemed from corruption, and the spiritual, that by which we are anointed. To drink the blood of Jesus, is to become partaker of the Lord’s immortality.
The Spirit is the energetic principle of the Word, as blood is of flesh. Accordingly, as wine is blended with water, so is the Spirit with man. The one, the mixture of wine and water, nourishes to faith, while the other, the Spirit, conducts to immortality. And the mixture of both—of the water and of the Word—is called Eucharist [lit. "thanksgiving"], renowned and glorious grace. They who partake of it by faith are sanctified in both body and soul.
For the divine mixture, man, the Father’s will has mystically compounded by the Spirit and the Word. For, in truth, the spirit is joined to the soul, which is inspired by it, and the flesh, because of which the Word became flesh, is joined to the Word. (The Instructor II:2)
For you abuse also our humble feasts, on the ground that they are extravagant as well as infamously wicked. ... But one sees the mote in another’s eye more readily than the beam in his own. ... The Salii cannot have their feast without going into debt; you must get the accountants to tell you what the tenths of Hercules and the sacrificial banquets cost; the choicest cook is appointed for the Apaturia, the Dionysia, the Attic mysteries; the smoke from the banquet of Serapis will call out the firemen. Yet about the modest supper of the Christians alone a great ado is made.
Our feast explains itself by its name. The Greeks call it agapè, i.e., affection. Whatever it costs, our outlay in the name of godliness is profitable, since with the good things of the feast we benefit the needy. It is not like it is with you: parasites do not aspire to the glory of satisfying their licentious propensities ... but as it is with God himself, a special respect is shown to the lowly. ... As it is an act of religious service, it permits no vileness or immodesty. The participants, before reclining, taste first of prayer to God. As much is eaten as satisfies the cravings of hunger; as much is drunk as befits the chaste. They say it is enough, as those who remember that even during the night they have to worship God. They talk as those who know that the Lord is one of their auditors.
After washing our hands and the bringing in of lights, each is asked to stand forth and sing, to the best of his ability, a hymn to God; either one from the holy Scriptures or one of his own composing—a proof of the measure of our drinking.
As the feast commenced with prayer, so with prayer it is closed. We go from it, not like troops of mischief-makers ... but to care as much about our modesty and chastity as if we had been at a school of virtue rather than a banquet. (Apology 39)
We take also, in congregations before daybreak and from the hand of no one but the presidents, the sacrament of the Eucharist, which the Lord commanded to be eaten at meal-times and instructed to be taken alike by all. … We feel pained should any wine or bread, even though our own, fall upon the ground. (De Corona 3)
Let every one of the faithful be careful to partake of the Eucharist before he eats anything else. For if he partakes with faith, even though something deadly were given to him, after [the Eucharist] it cannot hurt him. (Apostolic Tradition III:32:1)
Let all take care that no unbaptized person taste of the Eucharist nor a mouse or other animal, and that none of it at all fall and be lost. For it is the Body of Christ to be eaten by them that believe and not to be thought of lightly. ((Apostolic Tradition III:32:2)
For having blessed the cup in the Name of God you received it as the antitype [figure] of the Blood of Christ. Therefore, do not spill it, that no alien spirit lick it up because you despised it [and became] guilty of the Blood of Christ as one who despises the price with which he has been bought. (Apostolic Tradition III:32:4)
The names of the organs of sense are frequently applied to the soul, so that it may be said to see with the eyes of the heart … so it is said to hear with the ears when it perceives the deeper meaning of a statement. For this reason we also say that it makes use of teeth when it chews and eats the bread of life which comes down from heaven. (De Principiis I:1:9)
And, as the Eucharist is appointed for this very purpose, that it may be a safeguard to the receivers, it is necessary that we may arm those whom we wish to be safe against the adversary with the protection of the LordÕs abundance. For how do we teach or provoke them to shed their blood in confession of his name, if we deny to those who are about to enter warfare the blood of Christ? Or how do we make them fit for the cup of martyrdom, if we do not first admit them to drink, in the church, the cup of the Lord by the right of communion? (Letters of Cyprian 53:2)
[Christ's] mission and work it is to help against sin and death, to justify and bring life. He has placed his help in baptism and the Sacrament [i.e., communion/Eucharist/Lord's supper], and incorporated it in the Word and preaching. To our eyes Baptism [capitalized in original] appears to be nothing more than ordinary water, and the Sacrament of Christ's body and blood simple bread and wine, like other bread and wine, and the sermon, hot air from a man's mouth. But we must not trust what our eyes see. ("First Sunday in Advent" from Complete Sermons of Martin Luther, vol. V [Grand Rapids, MI:BakerBooks, 2007])
I [i.e., God] have given you baptism as a gift for the forgiveness of sins, and preach to you unceasingly by word of mouth concerning this treasure, sealing it with the Sacrament of my body and blood, so that you need never doubt. True, it seems little and insignificant that by the washing of water, the Word, and the Sacrament this should all be effected. But don't let your eyes deceive you. ("First Sunday in Advent" from Complete Sermons of Martin Luther, vol. V [Grand Rapids, MI:BakerBooks, 2007])
[commenting on John 6:44-55] The partaking of this bread is nothing but faith in Christ our Lord ... these words are not to be misconstrued and made to refer to the Sacrament of the Altar; whoever so interprets them does violence to this Gospel text. ... Why should Christ here have in mind that Sacrament when it was not yet instituted? (On Faith and Coming to Christ )
If anyone says that in the sacred and holy sacrament of the Eucharist the substance of the bread and wine remains conjointly with the body and blood of our Lord Jesus Christ, and denies that wonderful and singular change of the whole substance of the bread into the body and the whole substance of the wine into the blood, the appearances only of the bread and wine remaining, which change the Catholic Church most aptly calls transubstantiation, let him be anathema. (Canon 2, "Canons Concerning the Most Holy Sacrament of the Eucharist"; cited by Catholic Liturgical Library, retrieved on Sept. 17, 2013: http://www.catholicliturgy.com/index.cfm/FuseAction/DocumentContents/DocumentIndex/502)
The following canons concern the fact that the Roman Catholic Church only gives bread to their members in the Eucharist. Only the priest gets wine. This practice continues to this day.
If anyone says that each and all the faithful of Christ are by a precept of God or by the necessity of salvation bound to receive both species [i.e., bread and wine] of the most holy sacrament of the Eucharist, let him be anathema. (Canon 1, "Canons on Communion Under Both Species and That of Little Children"; cited by Catholic Liturgical Library, retrieved on Sept. 17, 2013: http://www.catholicliturgy.com/index.cfm/FuseAction/DocumentContents/DocumentIndex/502)
If anyone denies that Christ, the fountain and author of all graces, is received whole and entire under the one species of bread, because, as some falsely assert, He is not received in accordance with the institution of Christ under both species, let him be anathema. (Canon 3, ibid.)
But it is strange that it should be neglected by any that do fear God, and desire to save their souls; And yet nothing is more common. One reason why many neglect it is, they are so much afraid of "eating and drinking unworthily," that they never think how much greater the danger is when they do not eat or drink it at all. ...
I am to show that it is the duty of every Christian to receive the Lord's Supper as often as he can. ... The First reason why it is the duty of every Christian so to do is, because it is a plain command of Christ. That this is his command, appears from the words of the text, "Do this in remembrance of me:" ... A Second reason why every Christian should do this as often as he can, is, because the benefits of doing it are so great to all that do it in obedience to him; viz., the forgiveness of our past sins and the present strengthening and refreshing of our souls. ...
The grace of God given herein confirms to us the pardon of our sins, by enabling us to leave them. As our bodies are strengthened by bread and wine, so are our souls by these tokens of the body and blood of Christ. This is the food of our souls: This gives strength to perform our duty, and leads us on to perfection.
Let every one, therefore, who has either any desire to please God, or any love of his own soul, obey God, and consult the good of his own soul, by communicating every time he can; like the first Christians, with whom the Christian sacrifice was a constant part of the Lord's day service. And for several centuries they received it almost every day: Four times a week always, and every saint's day beside. Accordingly, those that joined in the prayers of the faithful never failed to partake of the blessed sacrament. (Sermons of John Wesley, Sermon 101)
That the consequence of Transubstantiation, as a conversion of the total substance, is the transition of the entire substance of the bread and wine into the Body and Blood of Christ, is the express doctrine of the Church (Council of Trent, Sess. XIII, can. ii). [reference to Council of Trent is in original; newadvent.org]