The Priestly Fraternity of Saint Peter (FSSP), a Society of Apostolic Life
In the early second century we already see a basic outline for the Holy Mass as it is known in the Latin Church or the Divine Liturgy as it is known in the Eastern Churches. Saint Justin Martyr explains to us in detail how early Christians assembled to worship the Lord .
“[O]n the day called Sunday, all who live in cities or in the country gather together to one place, and the memoirs of the apostles or the writings of the prophets are read, as long as time permits; then, when the reader has ceased, the president verbally instructs, and exhorts to the imitation of these good things. Then we all rise together and pray, and, as we before said, when our prayer is ended, bread and wine and water are brought, and the president in like manner offers prayers and thanksgivings, according to his ability, and the people assent, saying Amen; and there is a distribution to each, and a participation of that over which thanks have been given, and to those who are absent a portion is sent by the deacons. And they who are well to do, and willing, give what each thinks fit; and what is collected is deposited with the president, who succours the orphans and widows and those who, through sickness or any other cause, are in want, and those who are in bonds and the strangers sojourning among us, and in a word takes care of all who are in need. But Sunday is the day on which we all hold our common assembly, because it is the first day on which God, having wrought a change in the darkness and matter, made the world; and Jesus Christ our Saviour on the same day rose from the dead. For He was crucified on the day before that of Saturn (Saturday); and on the day after that of Saturn, which is the day of the Sun, having appeared to His apostles and disciples, He taught them these things, which we have submitted to you also for your consideration.”
He starts off mentioning that it is on Sunday, the first day of the week, that “all who live in cities or in the country gather together in one place”. He proceeds to mention the framework of the Mass.
(1) Liturgy of the Word
(2) Liturgy of the Eucharist
So he begins to mention the Liturgy of the Word in which “the memoirs of the apostles” and “the writings of the prophets are read”. Today the standard lectionary includes one Old Testament reading, a responsorial Psalm or hymn, an Epistle reading and a Gospel excerpt. This structure may change according to time and place, however, the readings are clearly there. After the last reading from the Gospel, the priest preaches the homily as sermon as in the passage it says “the president verbally instructs, and exhorts to the imitation of these good things.” After this, “all rise together and pray”; for centuries this has included the Nicene Creed — replaced with the Apostles’ Creed during some seasons — petitions and the offertory.
The second major part is the Liturgy of the Eucharist in which “the bread and wine and water are brought out” and the priest “offers prayers and thanksgivings”. It must be noted that we get the word Eucharist from the Greek term eucharistia meaning thanksgiving; so the sacrifice of the Body and Blood of Christ are there with the thanksgiving or eucharistia and become one action. He mentions the Eucharist to be “not as common bread and common drink” but the “the flesh and blood of that Jesus” “which no one is allowed to partake but the man who believes that the things which we teach are true, and who has been washed with the washing that is for the remission of sins, and unto regeneration” . So, only a baptized Catholic in good standing with the Church — or member of the Church — may receive Holy Communion (or Eucharist) as he “believes that the things which we teach are true . . . has been washed with” Baptism “for the remission of sins, and unto regeneration”.
There is more. The early Christian document The Didache mentions the Penitential Rite. It says, “every Lord’s day gather yourselves together, and break bread, and give thanksgiving after having confessed your transgressions, that your sacrifice may be pure” . Confessing our sins prepares us to worthily receive Holy Communion as Saint Paul says that “whosoever shall eat this bread, or drink the chalice of the Lord unworthily, shall be guilty of the body and of the blood of the Lord” . This, however, is for those in venial sin as those in mortal sin may not receive Holy Communion as canon law explains . This is because the Penitential Rite’s prayers do not constitute as a perfect contrition; there are exceptions to the rule as the same canon explains.
So, Saint Paul mentions the offertory, saying, “On the first day of the week let every one of you put apart with himself, laying up what it shall well please him; that when I come, the collections be not then to be made” . Though it is not for certain, due to ambiguity, that the collections mentioned were gathered at the church, even if it were not the case the Church decided to add it to the Mass since it is more convenient that way. It still should be noted that this was done on “the first day of the week”, which we know was already the day of assembly to worship the Lord and receive the Eucharist or break bread as seen in the Acts of the Apostles . Many Catholic writers such as Dr. Scott Hahn, Ph.D. have brought up an interesting notion that the entire Book of Revelation contains elements of the Mass. We see the author is brought up into Heaven and sees the heavenly worship on the Lord’s day . We see the presbyters or elders carrying thurifers or “gold bowls filled with incense”, offering “the prayers of the holy ones” . There is adoration in which they bow down in worship of the Lamb of God . Then there is the consacrated Host, the Body of Christ, which is “the hidden manna” . We remember Jesus Christ’s words that He is the true manna which came down from Heaven and that whoever eats His Flesh and drinks His Blood has eternal life . Dr. Hahn states that in the Book of Revelation, “the Church on earth gathers at the altar with the angels and saints in heaven”, so in other words at Mass “we participate with them” .
 First Apology, ch. 67
 Ibid, ch. 66
 1 Corinthians 11:27
 Code of Canon Law, Can. 916
 1 Corinthians 16:2
 Revelation 1:10
 Revelation 5:8
 Revelation 5:14
 Revelation 2:17
 John 6:51.54-57
 The Signs of Life: 40 Catholic Customs and Their Biblical Roots. New York: Doubleday Religion. 2009. Print. p. 40.