I am looking for the origin of the phrase "break bread" meaning to eat (or, I expect, to share food). I know that it can be sourced to the book of Acts but I have also seen many websites which say that it is older than that, reflecting a biblical era practice of sharing food to solemnize a meal, just with no actual references. What language does the phrase come from or is it an invention directly into the English?
We find it in the Wycliffe bible. I quote here from the 1395:
and weren lastynge stabli in the teching of the apostlis, and in comynyng of the breking of breed, in preieris (Acts 2:42 Wycliffe)
And ech dai thei dwelliden stabli with o wille in the temple, and braken breed aboute housis, and token mete with ful out ioye and symplenesse of herte, (Acts 2:46 Wycliffe)
And in the first dai of the woke, whanne we camen to breke breed, Poul disputide with hem, and schulde go forth in the morew; (Acts 20:7 Wycliffe)
Wycliffe worked from the Latin Vulgate, in which we find fractio panis.
However, the earlier Greek has the expression too:
ἦσαν δὲ προσκαρτεροῦντες τῇ διδαχῇ τῶν ἀποστόλων καὶ τῇ κοινωνίᾳ καὶ τῇ κλάσει τοῦ ἄρτου καὶ ταῖς προσευχαῖς (ΠΡΑΞΕΙΣ 2:42)
καθ' ἡμέραν τε προσκαρτεροῦντες ὁμοθυμαδὸν ἐν τῷ ἱερῷ κλῶντές τε κατ' οἶκον ἄρτον μετελάμβανον τροφῆς ἐν ἀγαλλιάσει καὶ ἀφελότητι καρδίας (ΠΡΑΞΕΙΣ 2:46)
Ἐν δὲ τῇ μιᾷ τῶν σαββάτων συνηγμένων τῶν μαθητῶν τοῦ κλάσαι ἄρτον ὁ Παῦλος διελέγετο αὐτοῖς μέλλων ἐξιέναι τῇ ἐπαύριον παρέτεινέν τε τὸν λόγον μέχρι μεσονυκτίου (ΠΡΑΞΕΙΣ 20:7).
[I could well be mis-highlighting the second example.]
While the practice of breaking rather than cutting bread, even when knives are available, is seemingly an old one, the expression is not heavily used in pagan sources, and is in Christian sources.
Edit: Could there be an earlier source?
Well, social sharing of food is probably as old as society; mammals generally feed their young, and chimpanzees share food they have collectively hunted, so we can imagine that there was some social value to food sharing among humans from whatever time you want to start calling them human.
For similar reasons, socio-religious sharing is probably as old as religion. It's found in ancient religion ("reversion of offerings" in Ancient Egyptian religion for example), and through to the very recent (of the top of my head, Judaism, Islam, Voodoo, Wicca, Hinduism all have some form of food sharing I can think of, even Jains end Paryushan with a communal meal, and they see starving to death as the ideal way for a monk to die).
Religious associations for bread, are likewise about as old as bread. The oldest cuneiform writings include Sumerian poems which are at once myths about the invention of bread, and bread recipes: Read the myth, and you're reading the recipe. (I haven't tried these, though I have tried one of the contemporaneous beer recipes, though alas without success).
And tearing rather than cutting bread is common everywhere from ancient times to today, and from peasants to haute cuisine.
So just about anywhere and any time, can we find what is needed for "break bread" to become a turn of phrase.
It does seem though that it doesn't exist earlier in this way. While some components are pretty universal as I suggest, and some tied into specific earlier views (e.g. combining the Last Supper and beliefs of the Second Coming, Isaiah 25:6-9 was now seen by the Christians as a prophesy of a new view on the Messianic feast), it seems the particular combination of these common themes gives us the expression.
Lack of evidence is not evidence of lack though. It also doesn't help that there are biases on such matters. Many Christian sources are biased toward claiming phrasings and customs they practice to be innovations of the early Christians. People inclined to revise Christian history (quite prominently many atheists, modern pagans and Christians of denominations that don't share a particular feature) are often biased toward claiming they aren't. In practice, each are as likely to muddy waters as the other. But while I've certainly seen Neopagans pointing to the provenance of bread-based traditions to argue "breaking of bread" isn't specifically Christian (and I'd quite agree for the reasons given above, though I disagree with the assumption that modern pagan forms are entirely uninfluenced by Christian Eucharist and perhaps even by Seder), I've seen nothing to suggest that the turn of phrase is; not even some spurious cases, and I've seen a lot of spurious claims about the provenance of all manner of things from pagans.
So, breaking bread is no more exclusively Christian than breathing air is, but the expression to break bread probably does originate with the early Christians.
The first citation in the OED for break bread is in The Wycliffite Bible (early version), from some time before 1382, and came from the Vulgate, a late 4th-century Latin translation of the Bible.
From Lament. iv. 4:
The litil childer askeden bred, and ther was not that shulde breke to them.
From Acts xx. 7:
Whanne we comen for to breke breed, Poul disputide with hem.
And from Mark xiv. 22:
Jhesus took bred, and blessinge brak, and ȝaf to hem.
Different parts of the Vulgate were translated from Hebrew, Greek, Old Latin and Aramaic.