not to be quickly shaken in mind or alarmed, either by a spirit or a spoken word, or a letter seeming to be from us, to the effect that the day of the Lord has come. 2 Thess 2:2
"nor by letter as from us"
The Judaisers had resorted to producing letters of commendation before the Corinthian believers (Read 2 Cor 3). The problem was acknowledged at the Jerusalem Conference:
Since we have heard that some persons have gone out from us and troubled you with words, unsettling your minds, although we gave them no instructions, (Acts 15:24)
Already this apostate system (in spirit) was working to undermine the faith of many sincere believers. History has shown how the RCC formulated "many words" to keep its relevance and holds its numbers.
The Apostles also gave no instructions to any within their teachings to create catechisms but many have been created.
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