No, most were like a Bible study in a house.
Have you looked at the archeological evidence which shows the layout of early house-churches? They were set up for liturgical worship. If they were sitting around having Bible studies which might resemble what many Protestants do today, how were they understanding the texts they were looking at? Who was guiding them in their exegesis?
They certainly were not letting the Scripture interpret itself, as the communities only had some, not all of the later-canonized New Testament writings. They were reading some gospels, some epistles, and what you would likely consider a bunch of superstitious fantasy, like the Acts of Paul and Thecla. I would actually be suspicious of Orthodoxy and Roman Catholicism if they lacked any references in their tradition to such works, as they themselves were a part of the life of the Church. Through its liturgical life, the Church has commemorated and preserved many of these stories within the tradition, at least those which were true and beneficial for the flock.
So anyway, the point is that they certainly would have been studying the Septuagint, which we still use in perfect continuity with not only the early Church but also with the LORD Christ, St. Paul and all of the New Testament quotations of the Old Testament. But beyond that they were confined to regional and communal texts, and there was a lot of ambiguity surrounding what were to be considered authoritative writings. Even if every house church had been full of literate Christians (which they were not), who all carried around pocket-sized Septuagints (which they didn't), they still would have looked to their bishop to teach them what they learned from the apostles. They would certainly not have looked to themselves for an authoritative interpretation. Those who did where infamous. They were the heretics.
The earliest house churches were not set up for liturgy. Peter's house was perhaps the first house church:For all intents and purposes, this house as originally built is indistinguishable from all other houses of ancient Capernaum. Its indoor living area is somewhat larger than usual, but overall it is about the same size as other houses. Its building materials are the usual ones. It was built with no more sophistication than the others in the region. In short, there is nothing to distinguish this house from its neighbors, except perhaps the events that transpired there and what happened to it later.- Editor, H. S. (2004; 2004). BAR 08:06 (Nov/Dec 1982). Biblical Archaeology Society[/b]
As for their exegesis, they relied upon God the Holy Spirit and the teachers He provided, and of course the word of the founding apostles and prophets:
26 How is it then, brethren? Whenever you come together, each of you has a psalm, has a teaching, has a tongue, has a revelation, has an interpretation. Let all things be done for edification.
27 If anyone speaks in a tongue, let there be two or at the most three, each in turn, and let one interpret.
28 But if there is no interpreter, let him keep silent in church, and let him speak to himself and to God.
29 Let two or three prophets speak, and let the others judge.
30 But if anything is revealed to another who sits by, let the first keep silent.
31 For you can all prophesy one by one, that all may learn and all may be encouraged.
32 And the spirits of the prophets are subject to the prophets.
33 For God is not the author of confusion but of peace, as in all the churches of the saints.
(1Co 14:26-33 NKJ)
This shows they could judge doctrine by the scripture:
NKJ Acts 17:11 These were more fair-minded than those in Thessalonica, in that they received the word with all readiness, and searched the Scriptures daily to find out whether these things were so.
(Act 17:11 NKJ)
Old Testament scripture was able to make Timothy wise unto salvation, now that God added the New Testament, how much more can it accomplish that feat?:
16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:
17 That the man of God may be perfect, throughly furnished unto all good works. (2Ti 3:16-1 KJV)However you are right there was confusion about which books were inspired, much of the NT was written to combat errors.
No doubt the bigger churches had Bishops who were instructed by the apostles, and house churches eventually merged with these "mega churches." But they were a feature throughout apostolic ministry:
19 The churches of Asia salute you. Aquila and Priscilla salute you much in the Lord, with the church that is in their house. 1 Co 16:19
15 Salute the brethren which are in Laodicea, and Nymphas, and the church which is in his house. Col 4:15
2 And to our beloved Apphia, and Archippus our fellowsoldier, and to the church in thy house: Phm 2
While this was somewhat chaotic, and no doubt gave rise to heretical opinions, the founding apostles and prophets shepherded them through it. It is likely the insistence of the early church upon apostolic teaching was born from the chaos of these early home churches.
Frankly I prefer one of these house churches where doctrinal disputes occur, than the super religious churches of today that are completely scripted. Chaos can be good. It does appear God like to personally tend to each one individually, and not have a King rule over them:
6 But the thing displeased Samuel when they said, "Give us a king to judge us." So Samuel prayed to the LORD.
7 And the LORD said to Samuel, "Heed the voice of the people in all that they say to you; for they have not rejected you, but they have rejected Me, that I should not reign over them.
8 "According to all the works which they have done since the day that I brought them up out of Egypt, even to this day-- with which they have forsaken Me and served other gods-- so they are doing to you also.
(1Sa 8:6-8 NKJ)
The only problem is they didn't remain faithful to the gospel, they added to it rather than accepting it was delivered to them full and complete:Beloved, while I was very diligent to write to you concerning our common salvation, I found it necessary to write to you exhorting you to contend earnestly for the faith which was once for all delivered to the saints. (Jud 1:3 NKJ)
There aren't multiple deliveries down through the ages, it was already "once delivered" when Jude wrote this.
That is why sola scriptura is preferable, then you learn the faith once delivered, without novelty that sprang up later. As Paul said scripture can make us complete, fully equipped, which includes knowing true doctrine, we have faith in God it is so.
Primitive Christianity is what it could be called, and like the church houses existing in apostolic times, we often disagree with each other...but I accept that chaos, just as the apostles did. Fact remains, sola scripturists agree theologically with each other in far greater percentage (90%+)than those who follow the Bible + their traditions.
The late Dr Walter Martin during a Melody-land lecture claimed some students quantified the internal agreement of Christendom, Orthodox Catholic, Protestant, on the major doctrines...and calculated it at about 80% agreement.
Given the body of data we have, its ancient nature, that level of agreement could be considered divinely inspired. Contrast the arguments of scientists and philosophers...much greater disagreement among them exists.
When you think about it, 80% may well be accurate. So even if an atheist tried to use our disunity against Christ, fact is, we agree with each other much more than scientists, philosophers, and atheists.
But alas, this prophecy came true:Another parable He spoke to them: "The kingdom of heaven is like leaven, which a woman took and hid in three measures of meal till it was all leavened."
(Mat 13:33 NKJ)