What is popular in the broadest sense is often not detailed or specific. By popular, I mean “of the people.” A popular audience is less academic, less trained in technical terms or the jargon of specialty. They tend to be generalists. This does not mean that advanced concepts cannot be packaged in a way to appeal to a popular audience. (The “For Dummies” books acknowledge this, i.e. Physics for Dummies.)
Evangelicalism is a popular movement; it is of the people, and so comes with the tendency to dismiss or downgrade specificity in theology. As one interlocutor on social media has said “We’re not saved by right theology.” This pastor has elsewhere explained what he means as “we are saved by ‘allegiance to Jesus.'” In so saying, he makes a distinction between theology and Jesus, but this is an elusive thing.
If one says “We are saved by allegiance to Jesus” someone may ask, “Who is Jesus?” And the answer—no matter what form it takes, is theology.
If I explain who Jesus is, I am theologizing. I am explaining (one hopes) from Scripture the details about the person and work of Jesus. If I feel unconstrained by Scripture, then of course anything is admissible. We cannot speak of who Jesus is without entering the realm of doctrine and theology. In this sense, we are indeed saved by theology. If my definition of who he is misses the mark of who Scripture portrays him to be, then it is foolish to think such “belief” means I am in a relationship with Jesus. It is akin to saying that someone who lost their money in a bank failure really shouldn’t have because they really, sincerely believed in that bank!
But which things about Jesus are the critical ones? We all know that there are details of theology that some like to insist on, details they ride like a hobby horse, but which for others are not primary. This is always a conundrum. Some say that Jesus did not descend into hell upon his death, others say he did. Scripture isn’t specific on this. If one makes that a doctrinal boundary, it’s not legitimate precisely because of the lack of specificity of Scripture on this. However, if one says that Jesus is not divine, he is not God, he is less than God, a created being, this gets to the very heart of his identity and is a fundamental difference in his person. I am now redefining his very essence. It is another Jesus this describes. Scripture, in numerous places, is specific about this aspect of Jesus’ identity.
Discerning this difference can sometimes be thorny, but in fact many of the lines I see people drawing do fall into these obvious categories. That is, some say it is not important whether Jesus physically rose from the dead (despite the NT insistence that without this, there is no salvation.) Or, they prevaricate and say “It’s important that it happened, but it’s less important to believe it. It’s still true even if we get it wrong.” Or, “it’s not critical to believe that Jesus is the uncreated and eternal Son of God. Arianism is still acceptable Christology.”
There are two things to observe about this. First, this mindset says that the revelation in Scripture is given for no particular reason, that the apostles and writers of Scripture have no certain expectation that Christians believe anything they’ve written. These things are offered for belief, but if you don’t believe them, it’s not significant, it’s not a boundary marker. You’re still a Christian.
Reading Scripture to say this is dubious at best, and textual malfeasance at worst. To take the resurrection once again, Paul insists it is part of the gospel message, and indeed if Christ is not raised, we have no forgiveness. To suggest that the fact of the resurrection is important to Paul, but he’s indifferent to whether the Corinthians (and others) believe this is to make Paul say the implausible. In Romans 10, he indeed links belief and confession of the resurrection to our salvation. It’s historicity presupposes our belief of it. Paul insists so vehemently on the resurrection because we must believe Jesus rose from the dead. In other words, we are saved by right theology about the person and work of Christ.
We can say the same for his deity. What John presents in his gospel prologue is a truth of Jesus as the eternal Word, with God in the beginning, and indeed, the agent of creation, not the object of creation. Looking back at this gospel, John says near the end “these are written so that you may believe that Jesus is the Christ, the Son of God, and that by believing you may have life in his name.” (John 20:31.) There is a whole lot packed into saying Jesus is the Christ, the Son of God, which John expounds in his first epistle, and in the Apocalypse. What one cannot say is that defining Jesus as a created being, or as one of many gods, fits into John’s definition, nor can one say that John is indifferent to whether people believe these things.
The second thing we can say is that the whole fabric of Scripture has to be employed if we’re to come to a biblical picture of who Jesus is, and what we must believe. It is sometimes the case that people camp out in the gospels, looking at the life of Christ as the whole of revelation about him. The importance of the gospel records is beyond question, but it’s also true that Jesus himself told the disciples there would be more. He was sending the Holy Spirit to guide them into the truth. Many of those truths are expounded in the epistles, and rather than presenting a Jesus vs. Paul dichotomy, the NT letters explicate the entailments of Jesus’ identity.
Note, I’m not saying that unless one signs off on all the bullet points in a doctrinal statement, one is not saved. Think instead of the regula fidei, or rule of faith, that operated in the early centuries. It functioned less as a doctrinal statement for believers and more as a winnowing agent to outline the boundaries of orthodoxy. The rule of faith didn’t have anything about church order, only the most rudimentary eschatology, but it did cover the deity of Christ and his death and resurrection, and Trinitarianism. The regula fidei is a precis of Scriptural teaching on these essentials. In short, yes, there are essentials.
Finally, Paul repeatedly urges “sound doctrine” in the pastoral epistles, and one wonders, why insist on this, if doctrine is of small importance? By looking at both testaments, the gospels, the epistles, all genres of Scripture—only then can we speak cogently about what Scripture says about Jesus. I know of no one who regularly does this who says this is a trivial exercise. But the alternative some are putting forth, a Jesus detached from the truth of God’s revelation, that the teaching of who Jesus is is somehow unrelated to a relationship with him, such an alternative is unfaithful both to Scripture and those to whom we present the gospel.