I was recently in a conversation with someone about the role of Christians in secular society. The person I was talking to used a common phrase, saying we should be "salt and light" to the non-Christians around us.
While I have heard the phrase quite a lot over the years, and have a fairly good grasp of what is meant by the term (that people might learn to accept Christ by our actions), it's not a phrase I care to use myself. This is mostly because it smacks of "Christianese," which I tend to avoid. That's not to say I disagree with the basic concept, but rather I prefer to use terms that people not steeped in Christian culture might use or understand themselves.
But that got me thinking: just where did this term come from in the first place? I looked up "salt" in my concordance, and the phrase "salt and light" does not seem to come from the Bible. Certainly, both "salt" and "light" are individually topics that the Bible discusses fairly often, but I don't see the words occurring together as a phrase. The closest I can find is Jesus' Sermon on the Mount, where Jesus tells his followers "you are the salt of the world" and "you are the light of the world" in successive verses (Matthew 5:13,14). Given that my TNIV actually puts the heading "Salt and Light" above these verses, I can only assume that this passage is the root of the concept, but it's worth noting that it's a concept derived from Scripture, rather than an actual quotation.
The "salt" verse is especially odd. Jesus tells his followers that "if the salt loses its saltiness, how can it be made salty again?" But this is a phenomenon that simply doesn't happen. Salt's flavor is a an inextricable part of the compound NaCl. There is no frame of reference for "non-salty salt." It simply doesn't exist! Some (but oddly, not all) commentaries acknowledge this reality, and there are various ways of understanding what Jesus meant here. One suggestion is that, because saltiness is an inextricable quality of salt, Jesus' followers were to be "salt of the world" as an inextricable quality of their own being. Another possibility is that, especially in the world of first-century Palestine, impurities could find their way into salt, causing it to taste differently. This would cause the salt to be useless as a seasoning. Given that first century audiences would be unlikely (to say the least!) to understand the intrinsic qualities of the chemical compound NaCl, this latter possibility seems more likely.
Many Christians would respond to this teaching by suggesting that Christians cannot allow the influences of the outside world to make us "impure," and some have even gone so far as to sequester themselves into exclusively "Christian" communities so they won't have to worry about becoming "impure" through outside influences.
But then Jesus follows up that teaching by telling his followers that they are the "light of the world." A light is only useful if it is seen by others. And just to make sure that he is not misunderstood, Jesus goes further: "...Neither do people light a lamp and put it under a bowl. Instead they put it on a stand, and it gives light to everyone in the house. In the same way, let your light shine before others...." (Matthew 5:15-16) Sequestering ourselves is no longer an option. We have to go out into the world, and that means we risk "contamination" by the impurities out there. So we have to be at least somewhat guarded, making sure that our salt is still pure as our light shines.
But the important part (at least to me) about all this is that this is a message for how Christians are to live in the world. We are called to see to our own behaviors. To borrow from another well known passage "first take the plank out of your [own] eye...." (Luke 6:42) Christians are not called to tell non-Christians how they are to act. Christian are to act in such a way that non-Christians want to become like Christians! We lead by example. If we believe (for example) that Jesus calls us to fidelity in marriage, then it's insufficient to tell people (especially non-Christians) that sex outside of marriage is wrong. We're called to lead lives of fidelity! Yet, the rate of divorce for Christians is not only no better than for average Americans, but in some cases, Christians actually divorce more often! (Disclaimer: the link does not echo my views in all respects, but I believe that the numbers cited are accurate enough) We are failing to be "salt and light" by our examples! Not only that, but by talking about such "values" so often, but failing to live up to them, we prove ourselves to be hypocrites, and non-Christians have every reason to ignore what we say.
Not only do we, as Christians tend to "talk" too much about these matters (and I have to include myself in this category, if only demonstrated by the amount of time I spend blogging....), but we tend to focus on all the wrong things! We "major in minors and minor in majors," to use a phrase I picked up ages ago. Christians often care more about whether someone watched an episode of Sex in the City (gasp!) than we do about whether we're following God's mandate to care for the poor and suffering.
If "they will know we are Christians by our love," where's the love?