Since this thread, I've learned about non-Christians joining churches so they can work from the inside to destroy it. Some report their success.
That does happen; it’s extremely rare however, for its more common for humans to succumb to the sinful passions and spiritual delusion (referred to as prelest by Eastern Christian theologians) than to execute grand designs of evil (even shockingly egregious cases such as the foundation of cults like the J/Ws were likely based more on prelest and passions such as pride rather than an intentional effort to lead Christians astray; likewise even in the case of monstrous heresiarchs such as Joseph Smith or Jim Jones, it appears that they believed their own nonsense and were highly delusional, as well as vainglorious).
That being said we do on rare occasions see people intentionally interfere with the operations of Christian churches; the recent disruption of a church in Minnesota on the unconfirmed rumor that the pastor was also an officer of a controversial law enforcement agency being one example of actual conspiracy against worship.
I would argue one of the largest-scale examples of an actual conspiracy to force a doctrinal change occurred in the case of the United Methodist Church, where after adoption of the Traditional Plan in 2018, people who disagreed with the established doctrine of the Church, which had always been its doctrine, rather than migrating over to another denomination that the UMC had entered into full communion with, such as the ELCA, decided to remain in order to change things, and went about this in a manner which is strange and unusual (I am unable to explain by what process an obvious majority vote in 2018 was changed into a minority vote in 2024; there is also the issue regarding the delay of the 2022 conference on the basis of Covid even though by that summer the pandemic crisis was regarded as being over for most Christians.
Now, to be clear, the Methodists doing this did so on the belief they were doing the right thing, and that traditional Methodist sexual morality was somehow opposed to the teachings of our Lord, or various other justifications; it was not, to be clear, an external conspiracy by atheists to attempt to destroy a denomination; this is less common, in part because most atheists just don’t care that much; it is much more likely for a church to be taken over by advocates of a change in doctrine than it is for a church to be taken over by those who wish to eradicate it.
Thanks for your question, I will try to outline the process we went through to the best of my ability:
The process first involved an interview with a pastoral search committee (made up on some board members, the interim pastor, and a couple people from the congregation). After this, we were selected from all the candidates that were interviewed to go for a weekend to the church and speak/meet the people (there were not multiple candidates selected to come and preach). During our weekend there, we met with the church board and were asked a variety of different questions/scenarios, but it was casual. We also had the opportunity to ask them any questions that we had. We were then introduced to the congregation on Sunday and had the chance to meet with people (although the week before we came, the church played a video of my speaking for the sermon that week). Directly after the Sunday service we were voted on by the congregation.
It was definitely quite the process and was not easy on the nerves lol. One thing I will say I am extremely happy for is that we are never voted on again by the church since we received the vote. I know of many churches where the pastor is a "term" position, meaning they are required to be voted on every 2 years! I can't imagine having to go through that process every two years. It is very interesting to see how this process is so different amongst churches (e.g., in some churches the board/district appoints a pastor).
I’m not a fan of this kind of ordination process, and the problems of avoiding this are one of the things that made me realize Congregationalism was not a great church polity; I have historic connections with Congregationalism and regarded it as acceptable in cases where another denomination was not serving a particular mission field, and justifiable from a Patristic perspective in that each diocese began with one congregation, albeit my view even while I was active in what is now an extremely left wing Congregationalist-related denomination, that it would have been ideal for bishops to be in charge of multiple parishes; I found myself not thrilled by the proliferation of megachurches with multiple campuses (the worst instance of this being Mars Hill in Seattle, where each satellite would play the sermon of Mark Driscoll, which was broadcasted or rather I think livestreamed from the main church using very hi-def video. I found this idea distressing; I believe each individual church ought to have a unique pastor, and that in the case of Mars Hill, what really existed was a diocese with parishes, albeit one in which the power of the de facto bishop was disproportionately immense (although some denominations give pastors once installed even more sweeping authority, such as the Calvary Chapel and the ”Moses model” of church polity, which resembles Congregationalism except that in the “Moses model” there is a lack of external oversight.
Now, to be clear, congregational polity churches are not the only ones to put clergy through the inferno of selection committees or equivalent processes; rather it simply seems like with Congregational churches this process is the hardest to avoid.