Update: I wish to question whether Christ authorises any human leaders for the churches. See for example Matthew 23.
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Are there ways to qualify and licence church leaders that are even more dependable than how societies qualify and licence physicians (medical doctors)? There are strong reasons to look for them: church leaders have even more responsibility, and power to do good or harm, toward people in their influence, than do physicians.
(1) Problem-based learning (PBL), used widely and successfully to prove whether a person can be relied upon as a physician, appears worthy of consideration also for church leaders. Can a person apply theological understanding to solve a comprehensive set of problems? A key here is that the New Testament lays out an evidence-based theology: a range of outcomes are witnessable through objective facts.
Other best practices from medicine potentially applied to church leadership are:
(2) Regularly recurring licence reviews that focus on the facts of a practitioner’s work (e.g. patient outcomes).
(3) Training in the basic sciences that enable a practitioner to detect errors and generally understand the process of reasoning and verification. Imagine a physician who does not understand mathematics, physics, chemistry and biology. He or she would be at the mercy of whatever “truths” the medical profession teaches.
(4) There may be even surer verification (qualification and licencing) methods for church leadership than for physicians. For example, when St. Paul, writing with St. Timothy, faced doubts about their authenticity as Christ-ministers, he presented a long set of criteria, in 2 Corinthians 1:3—6:10, all of which are fairly easily observed within a short period of time (again, here is evidence-based theology). A similar list of criteria for bishops, elders and deacons is found in St. Paul's letters, 1 Timothy 3:1-13 and Titus 1:5-9.
Is this surprising? It seems entirely predictable of God, who is perfect, and perfectly loving, that He would provide straightforward, highly practicable methods for identifying both trustable church leaders and untrustable ones (identified explicitly in texts such as Romans 16:17-19, 1 Timothy 6:3-5, 2 Peter 2, and 2 John 9-11).