One of the biggest surprises of That Royal Wedding sermon is the way that is has shown up the fault lines within evangelicalism in the West. I have been reflecting on this over the past week and it appears to me that there is a great deal that we can learn from the reactions.

What is an evangelical?

David Bebbington, a history professor at the University of Stirling, in his classic work, Evangelicalism in Modern Britain: A History from the 1730s to the 1980s,

gave four marks of evangelicalism which have stood the test of time: biblicism, crucicentrism , conversionism and activism. Evangelicals have traditionally been united across denominations, ethnic and social divisions (though not always) but often divided by issues such as believer versus paedo-baptism, charismatic versus cessationist, right versus left and Calvinist versus Arminian.

But today's world is very different. As the West increasingly rejects its Christian roots (while attempting to retain the fruits), the church overall is struggling to respond – and evangelicals seem to be losing their way. The key question is how we relate both to the Bible and to the culture.

I offer the following as a tentative way to understand what is going on in the evangelical church today. There are four major tribes within evangelicalism, each existing on a spectrum.

1. Liberal/Conservative

These evangelicals are primarily determined by their political/social positions, which they allow to determine their theological ones. The liberal side will identify with any 'progressive' cause going and re-interpret the Bible so that they can find 'biblical' justification for whatever is the cause celebre of the moment. Conservative is used here in a political/social, rather than a theological sense. Like the liberals they tend to find justification for their views from the Bible. Although they are at opposite ends of the political spectrum in many ways the two groups are very similar theologically – they determine their understanding of the Bible by their political/social views rather than the other way round.

As such they are often liberal in theology, with at least three of Bebbington's marks weakened; the only thing they are left with is the social/political activism. The Lib/Cons tend to capitulate to the culture. Many of the larger personalities in the evangelical world and sub-culture belong to this group.

In terms of Curry's sermon they generally loved it: the liberals because it pushed every one of their progressive buttons and was therefore clearly a 'gospel' sermon, the conservatives because it was after all a Royal wedding and one mustn't be critical of the Royals.

2. Broad evangelicals

These are those who would hold to all four of Bebbington's distinctives but see themselves as influencers of culture. They don't want to major on theology (in public) and are willing to work with others, while maintaining evangelical distinctives. They do not like to appear narrow and believe in a methodology which could best be described as both 'infiltrate' and 'trickle-down'. As regards the latter they believe that the best way to reach society is to reach the decision-makers, the gatekeepers, and so they place great emphasis on what could be termed 'strategic' evangelism. Aim for the top and there will be a trickle-down effect (of course they recognise the importance of the poor and will talk a great deal about social justice issues, but the reality is that the vast majority of the effort is spent on reaching those at the top – which is also where the money is that they need to resource their outreach).

They also tend to be much more willing to work in mixed denominations and with people of differing theologies because they believe that they can have an influence. They don't agree with wrong theology, but will tolerate it for the sake of peace and for the opportunity to influence. A seat at the table is more important than determining the menu – because you can't determine the menu unless you are sitting at the table.

Many of the large interdenominational evangelical organisations belong to this group. Its corporate methodology and tactics seem more conducive to them – as well as its focus on connecting with the culture and using the culture.

They regarded Bishop Curry's sermon as flawed, recognising it was not a gospel sermon, but believe it did contain gospel truths – which could be used as discussion starters or gospel opportunities. They are reluctant to criticise in case it makes them appear negative or too closely linked with the next group.

3. Separatist evangelicals

They too would hold to all four of Bebbington's criteria, with perhaps a little less emphasis on the social activism, because they fear being associated with a social gospel connected to liberalism. In fact this fear factor is an important element in their psychology. They have seen how the gospel has been contaminated by worldliness and heresy and so they desire to keep themselves as pure as possible.

One of the big problems for the separatists is that they are never quite sure who they should separate from. After beginning with separation from those who deny the gospel on primary issues (the atonement, the Bible, the resurrection, the virgin birth, sin, heaven and hell, etc) they quickly move on to secondary issues. They never know quite when to stop. Personal egos and empire-building can be as much as factor with this group (as indeed with all the others) as any doctrinal issue.

If they were watching the sermon at all (not being over keen on ritualistic state Anglican ceremonies) they would instantly have recognised it as heresy and immediately felt justified at their separation from evangelicals who did not have the discernment or the willingness to dissociate themselves from this kind of thing.

My problem is that when I look at these three groups I can, to some extent, sympathise with all of them. I understand the social activism and political engagement of the Lib/Cons. I admire the outreach and desire to influence of the broad evangelicals. And I appreciate the emphasis on purity and holiness of the separatists. But I just don't belong to any of them.

The Lib/Cons distort the gospel so much that sometimes I wonder if they have left the faith altogether – some have clearly moved far away from biblical evangelicalism. The broad evangelicals seem to tie in biblical theology with worldly methodology and ultimately I think that is to the detriment of the church and the gospel. I don't agree with the corporate trickle-down strategic approach – nor the low ecclesiology often found in these quarters. And the separatists are just too narrow and out of this world, although in another sense they are as worldly as anyone else. What tends to happen is that they separate their theology, worship and church life from their work and cultural lives, with the result that there is little interconnection between the two. So is there a fourth way? I think there is.

4. Puritan evangelicals

I can immediately sense the reaction. Weren't the Puritans the arch-separatists, a joyless bunch of theological nitpickers who were the Christian version of ISIS in their day?

Not at all. In general they combined a deep love of Jesus and scripture with an intense spirituality and a commitment to the reformation and renewal of both church and society. They did so on the basis of purity (hence the nickname) – not their own but the purity of the gospel. They were theologians of the Holy Spirit and passionate about the inner life being the key to the outer. Their attitude to culture was to engage with it without compromising their core beliefs, and also being prepared to challenge the culture whenever it went against the principles of the gospel. In this they could be regarded as prophetic. At their best their zeal was directed towards the goal that God would be glorified in church and society. At their worst they were miserable hypocrites.

A Puritan view would be both to abominate Michael Curry's sermon because it distorted, deceived and ultimately denied the Gospel, but at the same time to pray for all involved, love our enemies and to boldly and publicly proclaim the real gospel, whatever the cost.

My view is that we need a return to that Puritan view (although if anyone can come up with a better name please feel free). We need a high view of Scripture, prayer, preaching and the church. We need a holy courage and compassion in engaging the culture and an emphasis (in reality) on the poor and the voiceless within society. We need a clear commitment to orthodoxy (right doctrine) and orthopraxy (right practice) because we are in danger of being torn apart by adopting the world's values, especially on social media: tribalism, virtue signaling, identity politics, subjectivism, emotionalism and a lack of rationality.

Defeating the forces of evil will need all the spiritual weapons, fruit and gifts of the Holy Spirit at our disposal. In a world of alternative facts we need the truth of Jesus Christ more than ever. And how we need to truthfully, boldly and lovingly tell that truth.

If Bishop Curry's sermon prompts us to react in that way then we truly will know that the Lord works in mysterious ways.

David Robertson is associate director of Solas CPC in Dundee and minister at St Peter's Free Church. Follow him on Twitter @TheWeeFlea