I hear this question quite often, and my response—which is frustrating to some—is always the same. What do you mean by primary and secondary, and how do you determine what is primary and secondary? People often sort out their theological convictions in terms of primary and secondary, or essential and non-essential, or gospel issues and non-gospel issues. Unfortunately, few people have worked out a sound methodology for determining what is primary and what is not.
Before we determine what is primary and what is secondary, we need to figure out how we determine—we need to construct a sound methodology.
Some people appeal to the creeds (though they don’t always specify which ones and why) to tell us what is primary and what is secondary. But with same-sex marriage, this isn’t as helpful as people think. Some affirming Christians will show that the early creeds don’t have a statement on marriage and therefore a doctrine of marriage is a secondary issue. But nonaffirming Christians point out that the creeds were written largely in response to challenges to orthodoxy. And even heretics weren’t advocating for same-sex marriage. There’s no statement in the creeds because sex difference in marriage was taken for granted by all. (Thus, it’s similar to why Jesus never mentioned same-sex relationships.) Affirming folks may respond: That’s because same-sex marriage wasn’t even a category Christians considered. Nonaffirming people respond: exactly. And this is usually where the dialogue ends, or gets completely off track.
The creeds should play a role in shaping orthodoxy, but they can’t be the only pieces of evidence.
But what about the Bible? Shouldn’t we just let the Bible be our methodology for determining what’s primary and what’s secondary? Well sure, but what exactly does this mean? Some conservatives will say: If it’s clear in Scripture, then it’s primary. If it’s less clear, then it’s secondary. Some of my friends say that a pre-tribulational rapture view is crystal clear. Others think that 5 points of Calvinism is as clear as day—any true Bible reader will see this. John Piper and Wayne Grudem believe that “Egalitarianism must always lead to an eventual denial of the gospel” (Recovering Biblical Manhood and Womanhood, xi), which I suppose makes complementarianism a primary, gospel issue.
Regardless of whether you agree with these doctrines (perhaps you think they’re clear), the pressing question is: how do you determine what is clear? Interpretation involves a good deal of human subjectivity and imperfect intellect; it’s just as much an art as it is a science, and even science involves subjective interpretation. Theology is more like pottery than mathematics.
Some say male/female marriage is a gospel issue. And maybe it is, but I still need to know: what exactly do you mean by gospel issue and how do we determine if something is or isn’t a gospel issue? I suggest two possible methods. One, looking at how the word gospel is used in the New Testament (and Isaiah 40-55), and two, look at the content of gospel preaching in the New Testament.
A quick survey of the term gospel (Greek: euangelion, euangelizomai) doesn’t give us much in terms of same-sex marriage. We have several passages that warn against preaching a false gospel (Gal 1:6-9), but the content of this false gospel doesn't include an aberrant view of marriage—as important as this may be. There are several passages where false teachers are said to teach some sort of sexual immorality (Jude, 2 Pet 2, Rev 2, et al.), but as far as I can tell, the term gospel is not used in these passages. 1 Corinthians 15:1-5 is one of the main passage where the content of the gospel is explained, but there’s nothing there that mentions a particular view of marriage.
If we look at the content of gospel preaching in, say, the book of Acts (see chaps. 2, 7, 13, 17), it’s crystal clear (it really is) that the apostles didn’t weave a particular view of marriage into their message. Jesus himself never talked about marriage as part of his announcement that "the gospel of the kingdom is near."
Again, I’m not saying that male/female marriage is not a gospel issue. Maybe it is, maybe it isn’t. I’m only pleading for more methodological reflection when we make—or deny—such a claim.
Where does this leave us? It leaves us with a rather important methodological challenge. Whether you believe that same-sex marriage is a primary (like the Trinity) or secondary (like the rapture) issue, the coherency and compellingness of your view will be determined, in part, by your methodology.
So, is sex difference in marriage a primary or secondary issue? I don’t think it’s a secondary issue. I’ll explain why in my next post.