What does Acts 2:42 mean?

A favorite verse of Scripture for many (and rightly so) is Acts 2:42. After a whole bunch of people get baptized Luke writes, “They were devoting themselves to the apostles’ teaching and to fellowship, to the breaking of bread and to prayer (Act 2:42 NET).” But what did this look like? Was it disorganized hanging out? Or was there more to it?

Well, one of the earliest Christian writers, Justin Martyr, noted this in his defense of the Christian faith

“And this food is called among us Εὐχαριστία [the Eucharist], of 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, and who is so living as Christ has enjoined. For not as common bread and common drink do we receive these; but in like manner as Jesus Christ our Saviour, 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 unto us what was enjoined upon them; that Jesus took bread, and when He had given thanks, said, “This do ye in remembrance of Me, this is My body;” and that, after the same manner, having taken the cup and given thanks, He said, “This is My blood;” and gave it to them alone. Which 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.”

“And we afterwards continually remind each other of these things.  And the wealthy among us help the needy; and we always keep together; and for all things wherewith we are supplied, we bless the Maker of all through His Son Jesus Christ, and through the Holy Ghost. And on 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,3 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.”

Justin Martyr. (1885). The First Apology of Justin. (A. Roberts, J. Donaldson, & A. C. Coxe, Eds.)The Ante-Nicene Fathers, Volume I: The Apostolic Fathers with Justin Martyr and Irenaeus (pp. 185–186). Buffalo, NY: Christian Literature Company.

Note what occurs:

1. They gather.
2. They remind each other of what the Lord’s Supper means (as well as Baptism which is described in a previous passage).
3. The rich help the poor present. 
4. They bless God (presumably in song or recited benediction).
5. They read from the memoirs of the apostles (which in the first paragraph means the four gospels) and the prophets (the Old Testament). 
6. The president (one who presides) over the meeting exhorts those present to stay true to what was read. 
7. They pray.
8. They take the Lord’s Supper as spiritual and physical nourishment (and send it with deacons to those not present).
9. Those who have extra money give to the president (really like a modern pastor) who gives to those who are needy. 

So, when the book of Acts mentions that they gathered for fellowship, food, and discussing the apostles’ teaching they earliest Christians probably understood the passage to seem somewhat similar to what is described above, but allowing for differences of culture and church polity (things were much more free in Corinth compared to Ephesus). 

Also, the apostle’s teaching was apparently seen as summarized most fully in the four gospels because the early church saw the apostles’ as simply carrying the teachings of Jesus to the world. So the apostle’s teaching at the time of Acts was probably in obedience to Matthew 28:16-20. Their teaching was simply teaching others how to obey Jesus.