There is no more important Officer in the Christian Church, than the Elder. Whatever else Preachers and even Patriarchs and Apostles may be, they too are also basically "Elders." First Timothy 5:17f and Revelation 4:4-11 & 21:12-14.
One of the very words for "Elder" — Presbuteros in the Greek1 — has given the name 'Presbyterian' to perhaps the oldest2 denomination. Indeed, Presbyterianism is unthinkable without Elders. So too is the Biblical Church — from Genesis to Revelation, and beyond.
Here we deal with the following. (1) The evidence for Pre-Mosaic Eldership. (2) The Eldership in the time of Moses. (3) The Eldership in the time of Joshua to the Judges. (4) The Eldership in the time of the Monarchy. (5) The Eldership at the time of the Exile and the Restoration. (6) The Eldership during the Earthly Life of Christ. (7) Christian Eldership Develops from that of the Old Testament. (8) Degeneration of Eldership down to the End of the Middle Ages. (9) Calvin on Eldership in Genesis and Exodus. (10) Calvin on Eldership in Leviticus to Deuteronomy. (11) Calvin on Eldership from Judges to Jeremiah. (12) Calvin on Eldership from the Exile to Christ. (13) Calvin on the Eldership from Christ to Acts. (14) Calvin on the Eldership in the Christian Epistles. (15) Calvin's Summary of the Eldership in his Institutes. (16) Calvin on Post-Biblical decline of Elders till the Reformation. (7) Calvin resurrects Eldership at the Protestant Reformation. (18) Calvin's student Knox and the Scottish and Dutch Churches on Eldership. (19) Eldership in the Calvinistic Westminster Standards.