The following is taken from Eureka, Volume 2, sixth edition, written by the Christadelphian founder, John Thomas. It shows his advocation to prove all things and his claim that the community in practice was unwilling to do what it claimed to do. In other words he claimed it was unwilling to fully test its claims against scripture, but stood in traditions.
This was a challenging test for them because the Restoration Movement (which he calls Scotto-Campbellism) promoted unity based upon “the Bible alone” and without creeds:
“In those days, the author of this exposition of the apocalypse, then a young man of about thirty years of age, found himself among them, before he understood their theory in detail. He applied himself diligently to the thorough understanding of it by the study of the writings current among them. This he acquired; so that he needeth not that any should testify of Scotto-Campbellism; for he knows what is in it, and that it falls infinitely short of its pretension to be the “restoration of the ancient gospel and order of things.”
The author adopted with great zest and zeal the sentiment of their legend. He proceeded to “prove all things,” and to “hold fast what” he believed to be “good;” and to call no man father, teacher, or leader, but Christ, THE TRUTH (John xiv. 6). In doing this, he devoted himself to the study of the prophetic and apostolic writings, under the impression that he was engaged in a good work; and, as he was then publishing a periodical entitled The Apostolic Advocate, he would from time to time report to his brethren for their benefit, what he found taught therein. In pursuing this study, he found many of their principles to be at variance with “the word,” which was made void by them. Perceiving this, and supposing that the spirit of their legend was the spirit of their body, he did not hesitate to lay his convictions before them that they might prove them, and hold them, or reject them, according to the testimony. This raised quite a storm among them, the thunderbolts of which were aimed at him by the thunderer of their sect. This uproar caused the author to discover that he had made a mistake in his reading of their legends; and that their reading of Paul’s words was, “Prove all things which we have proved; and hold fast what we believe to be good;” and of Jesus, “Call no man father, teacher, or leader, but Alexander Campbell.” These were readings that he had never agreed to; and, therefore, he continued to read and publish according to the old method, very much to the indignation and disgust of the Simon Pures who misled the multitude.”