Telling which is which—food, drink, circumcision, sexual ethics, festival observance, idolatry, baptism, denial of the gospel, eschatological timelines—has been one of our greatest challenges as a church since the first century. How do we know whether something is the sort of thing we can agree to disagree about, or the sort of thing that renders someone anathema? We can all things of examples of groups who have made everything non-negotiable, and other groups who have left even essential Christian teachings open to debate. We’ve probably all used language of “primary doctrines” and “adiaphora”, or “closed hand” and “open hand”, or doctrines which are written in pencil, in ink or in blood. But how do we tell which is which?

There are a whole bunch of ways of answering that question, but because I’m a naive, biblicist bumpkin, I like this one: the Bible tells us. More specifically, Paul—the first Christian to wrestle with the problem, given the unique circumstances of his mission to the Gentiles—tells us. More specifically still, even if we were to limit ourselves to just one letter (and the one I’ve studied the most is 1 Corinthians, although it’s no doubt true of others), Paul tells us. So, for instance, here are some differences that clearly do make a difference:

- 3:5-17: Destroying God’s church through pride and divisiveness leads to destruction.
- 5:9-13: Sexual immorality, greed, idolatry, slander, drunkenness or swindling require that an individual be removed from the church.
- 6:9-11: Sexual immorality, idolatry, adultery, homosexual practice, theft, greed, drunkenness, slander and swindling are incompatible with inheriting the kingdom of God.
- 8:1-6; 10:14-22: There is only one God, and one Lord, Jesus Christ, and worshipping him is incompatible with participating in idolatrous worship.
- 8:7-13: Causing a brother or sister to stumble through idolatry could lead to their destruction.
- 10:1-12: Idolatry, sexual immorality, testing Christ and grumbling can lead to destruction.
- 11:17-34: Taking communion in an unworthy manner incurs guilt before the Lord.
- 12:3: The defining mark of a Christian is that they acclaim Jesus as Lord, by the Holy Spirit.
- 13:1-13: Love is non-negotiable.
- 15:1-11: It is of first importance that Christ died for our sins according to the Scriptures (cf. also 2:1-4), was buried, was raised from the dead, and appeared to many, which also means that Christians will be raised when Christ returns and destroys death.
- 16:22: If anyone does not love the Lord, they are anathema.

But on the other hand:

- 1:10-17: The person who baptised you does not matter.
- 7:6-11, 25-38: Whether or not an individual should get married depends on their situation, preference and gift.
- 7:17-24: If a person is circumcised, or a slave, then that is OK; if they are not, that is OK too.
- 9:3-18: Gospel preachers are entitled to travel with their spouses and receive financial support, but are not required to.
- 9:19-23: Christians are free with respect to all kinds of practices that might identify them as Jewish, Greek, law-observant, weak and so on.
- 10:23-33: It does not matter whether we eat or drink things that have previously been offered in sacrifice.
- 12:1-31: The spiritual gift(s) you have, and use, do not make you superior or inferior to other members of the body.

Now clearly, that list does not cover every possible subject on which Christians could disagree. It does not tell us whether Calvinism/Arminianism, or the timing of the millennium, are primary or secondary, let alone some of the big hairy debates of church history like Mariology or iconodulism or paedo-/credobaptism or the relationship between faith and works. As such, it could seem like a random list with few implications beyond itself (that is, someone could argue, it shows whether these specific issues are primary or secondary, but with no guidance on other issues which Paul doesn’t mention).

Notice four things, however. One: it does cover virtually the entire Nicene creed (the one God who created all things, the lordship of Jesus Christ by whom all things were made, his crucifixion, death, burial, resurrection, ascension and return, the Holy Spirit, the oneness of the church, baptism, the future resurrection, and eternal life), which is agreed upon by all Christians, everywhere. Two: it also includes several of the key issues of our day—issues over which some are saying that we should agree to disagree, but over which Paul is clear that drastic action needs to be taken. Three: any reasonably robust doctrine of Christian freedom will leave us assuming that, if an issue is on neither list, we are free to disagree on it (or, put differently, that if a biblical teaching is something over which we can brook no disagreement in the church, it will be identified as such). And four: there are other books in the New Testament. Just throwing that out there.

So, if someone suggests that we should really all agree to disagree about something—greed isn’t really a problem for a Christian, or idol-worship is a secondary issue, for example—then a quick glance at 1 Corinthians is probably worthwhile. There’s some good stuff in there.