The word presbuteros "elder", like most other eventual ecclesiastical terms, acquired its technical ecclesiastical sense gradually, but such developments build on earlier technical usages of the term. In the OT (LXX), the term is used to refer to village leaders who had administrative and judicial duties; one may think of the seventy "elders of Israel" of Exodus 24:1-4, Numbers 11:16 (representing the 70 sons of Israel and/or the 70 patron deities of the nations), the "community/town elders" of Leviticus 4:15, Deuteronomy 21:2-3, or the "elders and nobles" in 1 Kings 21:8, 11. In the literature of the Second Temple period, presbuteroi continued to refer to civic leaders (cf. "elders of the Jews" in Ezra 6:7 LXX, "officials and elders" in Ezra 10:8 LXX, the community "elders" of Daniel 13:5, 8 LXX), but they also referred to the Sanhedrin members specifically (cf. Acts 5:22) and leaders of local synagogues. Thus, in the synoptic gospels, one regularly encounters "elders of the people" grouped with the "chief priests" and the "teachers of the Law" (cf. Matthew 21:23, 26:3, 57, 27:41; Mark 14:43, 15:1; Luke 9:22, 20:1), or designated as halakhic tradents (cf. Matthew 15:2), tho the elders in this case probably has the sense of "ancient men" or "forefathers" (as in Hebrews 11:2).
In the NT, presbuteros in Christian usage is confined to Acts, the general epistles and the Pastorals; it is absent in the Pauline correspondence (Paul calls himself presbutés "the aged" in Philemon 9, but this is a different term), so a probable deduction is that this was not used as a technical term of status in Pauline churches, at least during Paul's lifetime. Acts however uses the term in reference to the apostolic period, and clearly describes it as a kind of office. Thus we find "apostles and elders" (apostolous kai presbuterous) in Acts 15:2, 4, 6, 22-23, 16:4, and the latter text places the "apostles and elders" in Jerusalem and describes them as deciding decrees. The term is used in a way that suggests that the reference is to the most important men in the movement who were not apostles. One may also think of later traditions of the Seventy (i.e. Dorotheus of Tyre), which ennumerate leaders of the early church outside of the Twelve, or the "pillars" described by Paul in Galatians 2:9 (which includes both Cephas and James the Just). Acts 14:23 refers to Paul and Barnabas as "appointing elders for them in every church", a passage that clearly denotes a kind of office tho the specific status is unclear. Is this a single presbuteros for each church (like the episkopoi "bishops" of the early second century), or a number of elders within each church (like the modern JW concept of "elder")?
Since Acts may well retroject later circumstances anachronistically into the early apostolic period, it is unclear whether the presbuteroi described therein pertain more from the time the book was written (i.e. after AD 95 imho) or from the period itself. The term is strikingly absent in Paul, but it appears in the Pastorals, written between AD 80 and 120. The Pastorals also give church order instructions for the episkopoi "bishops" and diakonoi "deacons" (cf. 1 Timothy 3) and assume a more developed ecclesiastical structure than in the earlier period. There are similar instructions for the presbuteroi (Titus 2:3) and for others concerning how elders are to be treated (1 Timothy 5:1, 19). That presbuteroi was a term of ecclesiastical status is indicated by the phrase hoi kalós proestótes presbuteroi "the taking-the-lead-well elders," suggesting that they had congregational authority. But was this a status accorded to esteemed older men, or was it an office that people regardless of age were appointed to (as Acts 14:23 would have it)? The texts are unclear. What is even more unclear is the use of the feminine form presbuteras in 1 Timothy 5:2 and Titus 2:3. Scholars debate whether this simply meant "older women" (suggesting that the presbuteroi correspondingly referred to older men of authority) or constituted a female office as well. Considering the patriarchal attitudes towards women in the Pastorals (e.g. 1 Timothy 2:9-15, 3:11, 4:7, 5:2; 2 Timothy 3:6; Titus 2:3-4), the second possibility seems less probable than the first.
In 1 Peter 5:1-5, the author writing in the name of the apostle refers to himself as a "fellow elder" giving instruction to the elders in the churches in a manner very similar to the Pastorals. Moreover, the term presbuteroi is contrasted with the neóteroi "younger men," clearly indicating that the term referred to older men with ecclesiastical status (as opposed to a particular office open to men of various ages), which is also the probable sense in the Pastorals. Their authoritative status is clear from such phrases as "shepherd the flock," "lording it over others," and "exercising oversight" in v. 2-3. What is not clear from these texts is whether there was a single presbuteros per church, or whether there were a body of elders in each church; the plural may simply the fact that 1 Peter is a general epistle addressed to multiple churches, tho the contrast with "younger men" may imply a number of elders in each congregation. James 5:14, in another general epistle addressed to multiple churches (1:1), makes reference to the "elders of the church" who have as among their duties healing the sick through prayer and anointing (cf. 1 Timothy 4:14 concerning the laying of hands by the presbuteroi).
It is in the Johannine writings and in Papias where we gain a clearer picture of the identity of the presbuteroi, at least in the early second century. The author of 2 John 1 and 3 John 1 refers to himself as "the elder" (ho presbuteros), and this individual is almost certainly the "John the presbyter" known to Papias of Hierapolis (writing c. 130-140) who was the "presbyter" of the church of Ephesus. Papias would cite him simply as "the presbyter", e.g. "And the elder (ho presbuteros) would say this..." (cf. Eusebius, Ecclesiastical History 3.39.15). Irenaeus, writing in Adversus Haereses (c. 180-190), also incorporated traditions from "the elders" which likely go back to the circle of Papias and are associated (erroneously?) by Irenaeus to the Apostle John. Papias himself used the term presbuteroi to refer to apostles and acquaintances of the apostles who were passing on Jesuine traditions, and specifically distinguished the "John the Elder" known to him (i.e. the leader of the church of Ephesus) from Apostle John:
"But I will not hesitate to supplement at any time for you too the interpretations with whatever I learned thoroughly and remembered thoroughly from the presbyters, since I am confident in the truth on their account. For unlike many I was not delighted with those who say many things but with those who teach the truth, or with those who remember not the commandments of others but those given by the Lord to the faith and derived from truth itself. But whenever someone who had followed the presbyters came along, I would carefully ask about the words of the presbyters, what Andrew or what Peter had said or what Philip or what Thomas or James or what John or Matthew or any other of the disciples of the Lord [had said], and what Aristion and the presbyter John, disciples of the Lord say as well. For I did not assume that whatever comes from books is as helpful to me as what comes from a living and lasting voice" (Papias of Hierapolis, cf. Eusebius, Ecclesiastical History 3.39.3-4).
It would seem here that the elders are men who, by virtue of their advanced age, are regarded as reliable sources of information about Jesus and thus have substantial personal authority, if not ecclesiastical authority as Aristion (linked to Pseudo-Mark in one MS) and John the Elder seem to have had. Overall, the picture seems to be that the presbuteroi were older men with considerable authority by virtue of their age and experience and who were the object of church order instructions like "bishops" and "deacons" were. But to what extent did the presbuteroi overlap with other offices (e.g. was John the Elder the bishop of Ephesus?) or include men who were considered young (e.g. were the presbuteroi appointed to the churches in Acts 14:23 all older men?)? There is much that is uncertain because the sources are too meager.
