What matters is that Darby have taken her account and started to preach the false doctrine of the pre-tribulation rapture .
Here some history facts about Darby's work
1825: British preacher Edward Irving revealed that he had been teaching some of dispensationalism's key aspects as early as late 1825. (John Darby-exalter R. A. Huebner has never even claimed to find any original prophetic idea in Darby before late 1826!)
1827-1830: Darby was still posttrib during these years. His 1827 paper had him waiting for only the posttrib "restitution of all things." After discussing in 1828 the "unity" of the church, he looked for only the Rev. 19 coming in 1829 and 1830.
1830: During the spring a young woman in Scotland, Margaret Macdonald, declared that she had discovered in the Bible what had never been seen by others: a rapture of "church" members described as a "pre-Antichrist" (or pretrib) event. Her words: "one taken and the other left" before "THE WICKED [Antichrist] be revealed." She was a partial rapturist seeing only part of the "church" raptured and the rest of the "church" left on earth. When she wrote that the "trial of the Church is from Antichrist," she meant the part of the church not included in her pretrib rapture. Leading partial rapturists including Pember and Govett have always applied the word "church" to the ones "left behind." Robert Norton, Irvingite historian and on-scene witness of Margaret's utterances, wrote that Margaret was the "first" to privately teach pretrib.
A September article in "The Morning Watch" (Irvingite journal) saw the "Philadelphia" church raptured before a "period of great tribulation" and the "Laodicea" church left on earth. Huebner's "Precious Truths" claimed that Philadelphia was seen raptured before only the "seventh vial" and not before "the great tribulation" even though the article writer added twice on following pages that this "period" was indeed "the great tribulation"! In the previous (June) issue the same writer had seen Philadelphia on earth until the final posttrib advent. In between these two issues, TMW writers had visited Margaret who explained her new "revelation" which was soon reflected on TMW pages without giving her credit! In December a published article by Darby was still defending the posttrib view!
1833: British lawyer Robert Baxter, an ex-Irvingite, wrote that the pretrib "delusion first appeared in Scotland" before it began to be taught in London the following year.
1834: A Darby letter referred to the new pretrib rapture view, stated that "the thoughts are new," and advocated the subtle introduction of it by writing "it would not be well to have it so clear"! Darby also called it the "new wine." Others who knew that pretrib was then a new view included other Plymouth Brethren, Irvingites, Margaret, and later 19th century historians such as Margaret Oliphant who referred to "a new revelation" in 1830 in western Scotland where Margaret Macdonald lived.
1837: Years after Darby supposedly had derived a distinction (or separation) between the "church" and "Israel," his 1837 article saw the church "going in with Him to the marriage, to wit, with Jerusalem and the Jews"!
1839: The first year Darby was clearly pretrib. His pretrib basis then (and during the next three decades) was Rev. 12:5's "man child" that is "caught up." But this "new" Darby teaching was actually a plagiarism of Edward Irving who had been using this verse for the same (pretrib) purpose since 1831!
1843: In a letter written from Switzerland, Darby referred to "the dissemination of truth and blessing...thus spreading on the right hand and on the left, without knowing whence it came or how it sprung up all of a sudden...." Here he gloated that others didn't know "whence" pretrib came or that he had advocated the subtle sneaking of the new pretrib view into existing groups (see "1834" above)!
1853: Darby's book "The Irrationalism of Infidelity" recalled his visit to Margaret Macdonald and her brothers in mid-1830. He remembered 23 minor details but carefully omitted the most important one: Margaret's teaching of a coming of Christ that would exempt believers from the great tribulation "judgments"----a detail that all others who visited her and then wrote accounts could easily remember! (It's obvious that Todd Strandberg's mother didn't soap his mouth enough because even though he knows better after the airing of "Open Letter to Todd Strandberg" on the internet, his falsehood-packed "Margaret MacDonald Who?" article on his "Rapture Ready" site continues to pollute minds by stating that I "have never been able to prove that Darby had ever heard of MacDonald or her vision"!)
1855: An article by eminent Brethren scholar S. P. Tregelles tied "Judaisers" to pretrib. But in an 1864 book he tied "Irving's Church" to pretrib. Both Huebner and Walvoord claimed that Tregelles contradicted himself, and Huebner charged Tregelles with "untruth and slander." But even William Kelly, Darby's editor, saw no contradiction and wrote, concerning "Judaising," that "nowhere is this so patent as in Irvingism"!
1861: Robert Norton, medical doctor and Irvingite, wrote that the "true origin" of pretrib had been "hidden and misrepresented." (This was about the time that Kelly was working towards the goal of elevating Darby and giving the false impression that Darby should be credited with the pretrib view.) Several pages later, in the same book, Norton revealed Margaret as the true originator of pretrib.
1863: In his "Five Letters" leading Brethren scholar Tregelles wrote that some Brethren had been unscrupulously issuing tracts by the thousands in which they changed the "words and doctrines" of "the Reformers and others" to give the impression that those ancient writers had actually been teaching the novel doctrines that some Darbyist Brethren were then circulating in the 1800's!
1864: Brethren scholar Tregelles charged fellow Brethren with changing even the words in ancient hymns: "Sometimes from a hymn being altered, writers appear to set forth a secret rapture of which they had never heard, or against which they have protested." I should add that in an 1865 letter Darby asked his editor to preserve the newer (pretrib) hymns and "correct the others," that is, the older (posttrib) ones!
1860's: From the 1860's to the 1880's William Kelly, editor of Darby's works, was busy putting together some volumes known as "The Collected Writings of J. N. Darby." Opposition to Darbyism had been increasing and Kelly was determined to fight it and continue to exalt Darby. His goal was to present a Darby that was prophetically "mature" long before he actually matured. He achieved this dishonesty with misleading words in brackets inside sentences in Darby's early works, and with footnotes that he "borrowed" from Darby's much later works when he was obviously more developed! Darby even gave this deviousness his blessing. In an 1865 letter to Kelly he wrote: "I should think that some of the Notes would require some revising....Even the sermons contain things I should not accept...." Kelly even flaunted his shameful manipulation in a footnote to Darby's 1830 article; the note said that "it was not worth while either suppressing or changing it."
More;
http://www.preteristarchive.com/dEmEnTiA/2005_macpherson_pretrib-diehards.html