It is generally argued by Protestants (primarily the Anabaptist Protestants) that the church structure of the episcopacy is entirely a new invention known to the church that did not originate in the Bible. But the reality is that the episcopacy was beginning to blossom into development already in the New Testament. Some of the Bultmannian scholars, such as Ernst Kasemann, have started to find the structures for early Catholicism within the pages of the New Testament.
Some Protestants contend that such a church structure is entirely Hellenistic but the truth is that such a church structure actually derives from the Qumran community of the Dead Sea Scrolls. Within the Qumran community, there was a hierarchical structure of a cabinet of twelve to fifteen men within the community council (kind of like today’s Cardinal-Bishops), an assembly called “the session of many” consisting of the mature members of the community which had judicial and executive authority and was most likely the instrument by which the community governed (kind of like today’s Bishops), and the priests who presided over the assembly (kind of like today’s sacerdotal priesthood).
In the early Christian church, there were the twelve apostles commissioned by Jesus who are given control over Israel much like the Qumran community is (1 QS 8:7-8, Ap 21:14, 1 QS 8:6, Lk 22:30). There was a “session of the many” which, under the direction of the twelve, presided over the Jerusalem church and made doctrine (Acts 15:12, 15:31, 4:32). Finally, the New Testament speaks many times of the bishop or overseer or episkopos (used in the Greek Old Testament to translate pqd and bqr. Both the Qumran and the New Testament indicate the roles of the baqqer, mebaqqer, and episkopos as equivalent (1 Pt 2:25, CD 13:9-10, Ti 1:7, 1 Tim 3:2-7, Ti 1:9, CD 13:5). And of course, all were chosen by the laying on of hands (cheirotoneo) (Didache 15:1, Josephus, Bell. II, 3: #123).
“Protestant scholars are coming to recognize that the idyllic simplicity and charismatic freedom which some of their forebears pictured as characteristic of the primitive Church simply do not fit the contemporary evidence” (Brown, 59).
(This has been a summary of Fr. Raymond E. Brown’s New Testament Essays, pp. 53-59)