I see three lessons, given in increasing order of importance.
1. Toon shows, as Ken Stewart has more recently, that the Reformed faith is not completely uniform. This isn’t to say there’s not a basic continuity from Calvin to Beza to the Puritans to Old Princeton to the present day. But at many points in Reformed history it’s not been neat or clear what the Reformed position is.
2. Toon gives a solid definition of Hyper-Calvinism and it’s not the same as being really, really Reformed. In common parlance, Hyper-Calvinist simply means “I think you are too much of a Calvinist.” But that’s not a fair use of the term. Historically, Hyper-Calvinism has referred to a set of theological conclusions and practices, none of which mark any of today’s leading Calvinists.
Here’s Toon’s summary (with some paragraph breaks added):
[Hyper-Calvinism] was a system of theology, or a system of the doctrines of God, man and grace, which was framed to exalt and honour and glory of God and did so at the expense of minimising the moral and spiritual responsibility of sinners to God. It places excessive emphasis on the immanent acts of God–eternal justification, eternal adoption and the eternal covenant of grace. In practice, this meant that “Christ and Him crucified”, the central message of the apostles, was obscured.
It also often made no distinction between the secret and the revealed will of God, and tried to deduce the duty of men from what it taught concerning the secret, eternal decrees of God.
Excessive emphasis was also placed on the doctrine of irresistible grace with the tendency to state that an elect man is not only passive in regeneration but also in conversion as well. The absorbing interest in the eternal, immanent acts of God and in irresistible grace led to the notion that grace must only be offered to those for whom it was intended.
Finally, a valid assurance of salvation was seen as consisting in an inner feeling and conviction of being eternally elected by God. So Hyper-Calvinism led its adherents to hold that evangelism was not necessary and to place much emphasis on introspection in order to discover whether or not one was elect. (144-45)
So the main tenets include: little attention to message of the cross, no free offer of the gospel to call, no summons for men to be born again, a highly introspective doctrine of assurance, and collapse of the hidden and revealed will of God. This was Hyper-Calvinism, not simply being seriously Reformed.
3. Most important, Toon explains how a healthy Calvinism became an unhealthy Hyper-Calvinism. His cites four reasons for the rise of Hyper-Calvinism in English Nonconformity.
First, after 1660 orthodox Calvinism was under siege. “The religious leadership of the nation was lodged firmly in the hands of men who were either Arminian or moderately Calvinistic in theology” (146). Given this opposition, many Calvinists adopted a bunker mentality. They saw themselves as the small remnant that still clung to the apostolic faith. As their faith became increasingly defensive, it became rigid and less attractive.
Second, the intellectual environment of the time was one that greatly emphasized the role of reason in religious faith. Consequently, the Hyper-Calvinists applied strict logic to biblical doctrines that led to unbiblical conclusions. If election is true and grace is really irresistible, why both with the free offer of the gospel? This was rational logic, but not biblical logic.
[Update: “Rational” is probably not the best word choice. It can give the impression that biblical logic is irrational. Biblical logic adheres to the rules of rationality, but as constrained by all the biblical data on a subject. The Father is God; the Son is God; the Holy Spirit is God. But we would be wrong to deduce from this that there are three gods, because the Bible also clearly states that there is only one God. I like what one commenter below said: “Hyper-Calvinists applied strict logic to biblical doctrines without considering ALL the relevant biblical doctrines, therefore leading to unbiblical conclusions.”]
Third, many of the leading Hyper-Calvinists were “capable of making extreme changes in thought” (147). They had no patience for nuance or tension. They were prone to extremes. They latched onto one way of thinking and felt like the only safe course of action was to take that thinking all the way to the edge.
Fourth, they were not very intelligent. That may sound cruel, but listen to Toon:
The Hyper-Calvinists were sincere men of average intelligence, but they lacked a prophetical and discerning spirit. They keenly desired to glorify God and mistakenly believed that God was more glorified by the exaltation of free grace in the pulpit and the printed page, than in the evangelism and conversion of men. They became so obsessed with the defence of what they regarded as sound doctrine that the evangelistic note of Scripture as basically an overture by God towards sinners was muted. (148)
We often have a populist view of theological error, that most mistakes come from people too smart for their own good. But that’s not always the case. Many serious errors creep into the church because pastors and leaders are not sufficiently careful, discerning, and intelligent to see subtle misdirections in emphasis and logic.
These four errors are always real temptations for God’s people, not least of all for Calvinists. We must be careful thinkers, beholden to biblical texts not to logical deduction. We must beware of our own personalities at times and on guard against an us-against-the-world ethos. Most critically, we must be sure there is no embarrassment over conversion and the call of the gospel to repent and believe. A cautionary tale indeed.