I have long struggled with whether to call the RPCNA "legalistic". On its face, using the term legalism implies that RPs believe in "works-based salvation". Even though works are central to how that church operates, I don't believe any RP member or pastor would claim that they were saved by their works, so it's always seemed not quite right to call the church "legalistic".
Reading a book on purity culture recently, the author used the term "purity prosperity gospel". This immediately struck me as a better way to think of the RPCNA's focus on works. In purity culture, the equation that was pushed was that discipline now led to a guarantee of marital bliss. For a man, staying celibate until marriage, never dating, never viewing porn, never getting physical with a girlfriend and avoiding emotional attachment at least before engagement would mean that the honeymoon night would be amazing. For a woman, similarly, checking emotions, never wearing 'provocative' or 'revealing' clothing, staying celibate meant that the marriage would be wonderful and happy.
This led to what might be called the marriage myth, which led to the marriage disillusionment. Christians who did everything right found disappointment on their wedding night (Sheila Gregoire's study revealed that vaginismus was common among women who held purity culture beliefs) and potentially in marriage because they were encouraged to find the one right person.
Purity culture then becomes a lens into this quasi-legalistic, quasi-heretical view of God found in Evangelical and Reformed churches.
RPCNAs may have held books like The Prayer of Jabez at arms length, but they embraced books like Parenting by God's Promises. I haven't read The Prayer of Jabez, but my understanding is that it is based on Jabez's prayer for prosperity, which the Bible simply notes that God granted to him. So, the premise, as far as I've heard is that we can pray for peace and material possessions and God will(*) give it to us. I'm sure, like Beeke's parenting book, there are lots of hedges around the central point.
These books, and the related prosperity-gospel culture propose a view of God, which some have called the "Magic god", a god who obligates himself to give things to people based on an incantation or ritual. Beeke does waffle on God's "Promises" a bit, probably to satisfy potential critics, but his contention is that God promises to bless parenting that follows the rituals that Beeke has laid out, most notably severe discipline and regular family worship. Parents who neglect this will almost certainly annoy God and their children will become wayward.
When we look at Evangelicals broadly, we find this ritualistic language in common discourse. In Christian political discourse, I often see: "if my people, who are called by my name, will humble themselves and pray and seek my face and turn from their wicked ways, then I will hear from heaven, and I will forgive their sin and will heal their land." (2 Chr. 7:14) This becomes a Christian Nationalistic ritual. If we can only pass Christian laws and declare ourselves a Christian nation, then we will force God to bless us.
This brings up another interesting point - the American Dream / Myth is a similar ritual. So, interwoven with this idea of Christian Nationalism is the idea that morality = wealth and wealth = morality. We may not consider Elon Musk or Warren Buffett the epitome of Christian morality, but we do look at a person sleeping in their car as inherently immoral, due to this equation. Both sides of this equation come into play
So, back to the RPCNA. Because they have adopted this idea of a "magic god" their view of the Christian life comes down to a list of do's and don't's. A person living life within those guardrails can expect all the good things in life from God (except that God sometimes allows bad things to happen to good people), and a person living life outside those guardrails can expect all bad things in life from God (except that God is gracious and doesn't always give people those consequences). Conversely, a person whose life is going well is most likely living within those guardrails and a person who is experiencing trouble is most likely outside those guardrails. Therefore, it is the job of the elders and pastor to find members who are experiencing bad things in their lives and figure out how they have strayed outside the guardrails.
Of course, in typical RPCNA fashion, the asterisks(*) on the RPCNA prosperity gospel give the authorities the crack in the door they can stick their foot into. A pastor/elder who is experiencing bad things is, most likely, still within the guardrails, but experiencing a Satanic attack. Allegations of abuse? Satanic attack. Under investigation by CPS? Satanic attack. Conversely an ordinary member with allegations of abuse must be investigated, and a normal parent under CPS investigation probably needs strong questioning by the session.
Sessions tend to be militaristic in their behavior towards people they think are living outside the guardrails because they think that somehow the church will be poisoned by the person living in sin. They might think they have an Achan in their midst, or think about the man in Corinth who was living in visible sin who needed to be put out. Again, the prosperity gospel strikes. A church can only experience blessing if it is living in the guardrails, and that likely means that all members must be living in the guardrails, and all members who are not living in the guardrails must be identified and put under discipline so that they either repent and return within the guardrails, or they leave and thus the church returns to the pure state. Sometimes this inquisition-like behavior becomes so severe that it seems like, "will the last perfect person who discovers they're imperfect, please turn the lights off on your way out?"
I hope this concept of "RPCNA prosperity gospel" gives you a better framework to describe your legalistic experience in the RPCNA. Not exactly works-based salvation, but works so central to what it means to live a right life and being under constant scrutiny. I believe this is an American cultural view that has become established in the church - the same view that pushes political parties against compromise and blames people in the worst of circumstances as if it must be their fault. Ironically, the exact thing the book of Job was meant to explain. American Evangelicals have all proudly put on the garments of Job's friends. Job 4:7 - "Consider now: Who, being innocent, has ever perished? Where were the upright ever destroyed?" Job 8:4-6 - "When your children sinned against him, he gave them over to the penalty of their sin. But if you will seek God earnestly and plead with the Almighty, if you are pure and upright, even now he will rouse himself on your behalf and restore you to your prosperous state." - Job's friends would have made wonderful RP elders.
