Denominations and sects that have emerged since the post-Enlightenment (supremacy of human reason) period in the 1800s can be characterised by a claim to reject the centuries of theological discussion and return to the “original apostolic faith.” Christadelphians believe that this faith can be recovered from an “unbiased” reading of the Bible for oneself. The founder of the Christadelphian movement, John Thomas, apparently determined to find out “the truth of the matter” after a near-death experience. Eventually, he decided he’d found the core of this truth and wrote a book entitled Eureka (from the Greek eurisko, to find). The movement has since espoused the view that “Christendom,” (by which they mean essentially all of the Christian church in its various forms over the centuries) rapidly departed from the Truth of the New Testament into apostasy. Only in these “latter days” has this Truth been rediscovered, by John Thomas and his followers, the “Brothers in Christ.” Admittedly, they do acknowledge that there have been other “remnants” of the faithful, such as Socinians and Anabaptists who have recognised some, but not all of the Truth. 
There are several problems with this “rediscovery of the Truth after 1800 years” kerygma. Although Christadelphians make Bible reading central and have an enviable knowledge of Scripture, they are not, nor have they ever been, exclusive in this. To claim, overtly or by implication, that no one else in the history of the church has ever known the Bible as well, or understood it as correctly, or appreciated its core truths as one community does, is a bit of a stretch, perhaps even arrogant. It is true that before the Bible was readily available in the common languages of regular people, the Roman Catholic Church dictated the doctrinal views and practices of Christians. During this time there were significant departures from basic biblical teachings, primarily because the Church held itself to be an authority over Scripture, as the Roman Catholic Church still does today. Only when brave scholars such as Wycliffe, Hus, Luther, early Anabaptists etc, began reading the Bible more objectively, sitting under its authority and working to make it freely available to all, did a doctrinal renaissance begin. The doctrines of Scripture alone, salvation in Christ alone, by grace alone and through faith alone, to the glory of God alone resurfaced and became the foundations of Protestant doctrine. Interestingly, the doctrines of the triune God and the deity and humanity of Christ were still recognised to be scriptural, even by the Anabaptists with whom Christadelphians claim an affinity. These doctrines can be demonstrated to have been believed and taught from the very earliest times post-Christ and definitely pre-date the medieval Roman Catholic Church and its papacy.
The troubling issue for the exclusive Christadelphian claim to the “Truth” is not that they are a minority. That was also true of the very early church, of the early reformers, and of persecuted believers in the world today. The majority are not always right and there is a demonstrable “remnant” theology through Scripture. The issue, rather, is the basis of the claim. Christadelphians, unlike some other groups with exclusive truth claims, do not claim a special revelation of the Holy Spirit, or divine revelations on golden plates, or newly discovered “gospels.” They vehemently reject any authority but the Scriptures and suppose this to be untrue of other Christians, who have been heavily influenced by “authorities” such as the papacy. The basis of the Christadelphian claim to be virtually unique in their grasp of the whole Truth is simply their claim to have a better understanding of the Bible because they (alone?) read it with an open mind.
“The churches are full of darkness, for the Gospel doth not shine into them, being neither believed nor preached among them,” claimed John Thomas in 1850.  Robert Roberts, writing in 1862, states that “Christendom is astray from the system of doctrine and practice established by the labours of the apostles in the first century” and claims that “it is for every man by himself, and for himself, to seek to understand it…”  Harry Tennant affirms that “Christadelphians do not believe that any of their members, past or present, have received any special revelation direct from God… the Christadelphian faith rests squarely and solely on the Bible as the word of God.”  Tecwyn Morgan explains in detail the expected findings when you “Work it out for yourself.”
The confronting thing is, other truth-seeking Christians through the centuries have also affirmed the Bible as the sole authority for life and doctrine, affirmed its sufficiency and inerrancy, and immersed themselves personally in the study of its teachings. Where did they all go wrong, one might ask? Did they not pray as earnestly and sincerely as John Thomas? Did they perhaps not read all of the Bible? Maybe they didn’t read it often enough, or in the right language? Maybe they weren’t learned enough (but see Prov 3:7; 9:10; 26:12 and 1 Cor 1:17, 25-2:16) Or perhaps they were too learned! Or maybe they are still suffering the “tormented experience of the orthodox hallucinated” as Roberts claims. Roberts’ explanation is that the Reformation was “only partial” and since then, people have been “trained and indoctrinated into the Protestant catechisms” such that “the position was not favourable to the exercise of independent judgement” and doctrines were thereafter accepted by “mere force of habit… and this is the position of the clergy to the present day.”
If Roberts and later Christadelphians are right, then Scripture is clear enough for them to understand, but everyone else has been so biased by what they have been taught within “the churches” that they have a completely blinkered approach to the Bible. If indeed, the Bible is so obvious in its teaching that “common attention which the commonest of common sense would prescribe” and “earnest and independent study of the Bible” are the only prerequisites for discovery of its truths, then Christadelphians are effectively claiming that they are virtually the only ones in two millennia who have achieved this! However, one has only to read the Chicago Statement on Biblical Inerrancy and the historical confessions of faith to see the high regard in which gospel-oriented Christians hold the authority and sufficiency of Scripture. So Christadelphians are not the only ones to believe that the Bible is the sole source of theological truth, or to devote their lives to its study. How then is it that, for 2000 years, virtually nobody else who has spent their lifetime engaged in prayerful, open-hearted attention to the teachings of scripture has reached the same conclusions as this latter day group of Bible students?
I would like to respectfully suggest that Christadelphians are not as objective, unbiased, knowledgeable or open-minded concerning the Scriptures as they believe; two reasons are offered. Firstly, their position is based on the sufficiency of human effort in coming to a knowledge of the truth. Secondly, despite all their emphasis on open-minded reading of Scripture, they are one of the most doctrinally constrained and prescriptive groups to wield the Bible today. Christadelphians have traditionally rejected a personal working of the Holy Spirit in the lives of believers today.
“…the Spirit has no participation, except in the shape of the written word. This is the product of the Spirit — the ideas of the Spirit reduced to writing… The present days are barren days as regards the Spirit’s direct operations.”(Roberts) “God’s will was brought into action by His Spirit. None of this is known other than by the Word of God which is the message of the Spirit.” (Tennant).
This is in contrast to the Scriptural teaching that the mind of the unregenerate person is unable to appreciate the truths of God; we are spiritually dead until God’s Spirit awakens us to spiritual truth in the “new birth.” To understand and apply God’s word does not need priestly interpretation, the authority of the pope or a set of written doctrines, but it does need the work of the Spirit in the human heart. Human reasoning apart from the work of the Spirit is insufficient to allow God’s word to work in our hearts (Jer 17:9; John 3:10; 15:5; Acts 8:30–31; Rom 5:5–6; 7:18; 8:8; 1 Cor 2:14; Eph 2:1–6; Col 2:13; Titus 1:15).
This, I believe is the answer to the dilemma. Christadelphians deny that it is possible to “have the Spirit” today, or to exercise his gifts (miraculous or not). They specifically reject that the indwelling of the Spirit is required for reception of the Gospel. Therefore, they have reached their understanding of God’s word by human effort. This is entirely consistent with their position that they must contribute human effort to their salvation  But the Bible itself teaches that the Holy Spirit, who authored Scripture, must open a person’s mind and heart to its truths (Mat 16:17; John 3:3–12; 14:26; Acts 16:14; 1 Cor 2:4–16; Eph 2:8; Phil 1:6)!
Now we have received not the spirit of the world, but the Spirit who is from God, that we might understand the things freely given us by God… The natural person does not accept the things of the Spirit of God, for they are folly to him, and he is not able to understand them because they are spiritually discerned (1Co 2:12 –14).
For Christadelphians, the window into the truths of God’s word, the basis of their common fellowship with one another and the expected result of an individual’s study of Bible teaching, is expounded in a very specific list of doctrines to believe versus doctrines to be rejected. If one’s earnest, unbiased reading of Scripture, applying common sense and reason prayerfully, causes one to arrive at a different conclusion from some aspect of this detailed list, then unfortunately that person cannot be “in the Truth.” This becomes a circular argument; an unbiased appreciation of God’s word must lead a truth-seeker to reject the doctrines of “Christendom” and embrace the doctrines of Christadelphia. If another conclusion is reached, the truth-seeker must not have truly approached the Scriptures with an open heart and mind but be influenced by the teaching of “the churches.” But is this really true? A critical examination of this idea is found at (http://www.christadelphianresearch.com/viewofthebible.htm, accessed 25/10/15)
If it took such uniqueness of mind and independence of thought to recover the true saving gospel then it is worth examining the idea of independence of thought as to its limitations. This is after all what the Christadelphians claim the recovery of the original saving gospel rested upon. If the lack of independence of thought and the suppression of truth was a factor in mainstream Christianity, then it is possible to apply to the Christadelphians too. We also have to consider the possibility that independence of thought and the Bible alone may not be the route to God. It may not be possible for most folk, we may need the aid of God himself in some way and it may impossible to avoid reading some of our own thinking into such a search by such a method.. This belief that truth and salvation comes through personally searching of the scripture and without any direct help or guidance from God has deep theological implications with regard to ancient questions about predestination and freewill. It also encompasses a huge belief in the ability of the human intellect and sees little of a role for emotion in the process of conversion… The controlling spirit of the community… grew from what (John Thomas) saw as a natural consequence of following to a conclusion principles he himself was taught, to “prove all things,” that the Christadelphians themselves now suppress in the exact creedal way he advocated against.”
In contrast, a return to true apostolic doctrine and practice would be expected to result in less need for detailed doctrinal statements, not more(!) and certainly not to the level of detail found in 30 “truths to be received” (including a compulsory premillenialist position) and 35 “doctrines to be rejected,”( including the explicit rejection that the Gospel alone will save, without obedient works — contra Eph 2:8, Rom 1:16 and the NT generally ) Here is what was actually required by the original apostolic faith, for a person to be considered saved (see also Acts 11:14, Rom 8:30, 10:10, 13, 1 Cor 1:18, Titus 3:5, 1 John 5:13; Heb 6:1-2).
And it shall come to pass that everyone who calls upon the name of the Lord shall be saved.’ (Acts 2:21)
And they said, “Believe in the Lord Jesus, and you will be saved, you and your household.” (Acts 16:31)
If you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved. (Rom 10:9)
So, dear Christadelphians, my heart’s desire and prayer to God for you is that you may be saved, not in your own strength but in his, that you will know the only true God and Jesus Christ whom he has sent, and that you will receive his Spirit in your hearts to cry “Abba, Father,” and be led into all truth.
- Alan Eyre, The Protesters (Birmingham: The Christadelphian, 1975) and Thomas E Gaston, ed. One God the Father (East Boldon: Willow, 2013)Part Two: History.
- John Thomas, Elpis Israel (reprint Birmingham: The Christadelphian, 2000) vii.
- Robert Roberts, Christendom Astray (West Beach: Logos Publications, 1984) Lecture 1
- Harry Tennant,The Christadelphians: What they believe and teach (Birmingham: The Christadelphian, 1998) vii.
- Tecwyn Morgan, Understand the Bible: Work it out for Yourself (Birmingham: The Christadelphian, 2006)
- Christadelphian Statement of the Faith articles XVI, XXIV and Doctrines to be Rejected 24 & 25. http://www.christadelphia.org/basf.htm
Further reading on Christadelphians as a “sect” rather than a “cult” or “denomination” may be found at http://blog.dianoigo.com/2016/01/are-christadelphians-cult-sect-or.html.