The call for Christians to be salt and light is used like a war cry by many. It is often used to make Christians feel guilty for not doing enough or not speaking up enough or not giving enough, because if they did then surely “the world” would be changed. Surely “the world” would trust and follow God. Surely “the world” would be a beautiful place where no one is in need and no one fights. Only the passage wherein Jesus talks about this (Matthew 5:13-16) does not instruct or command Christians to be salt and light. In context, he is actually telling his disciples they ARE salt and light. He mentions this right after telling them to be encouraged when they are persecuted, and right before telling them that the true application of God’s law has to do with the heart rather outward rule following. They do not yet know about living by the power of his spirit in the freedom of his grace, but he is preparing them to tell the message of hope once it is time.
What needs to be considered is:
1. How do the metaphors apply?
2. What is the world?
3. Is change in someone anyone else’s responsibility?
4. Is there any indication that the world is going to change?
5. What are good works, anyway?
Fortunately, Jesus defines the metaphors as he uses them. He is referring to the seasoning that salt provides and the way light helps people see. There are many other scientific and cultural aspects of salt and light that are interesting, but apparently those are not what Jesus had in mind. Not that God can’t be creative with words, but in this instance both metaphors, as Jesus clarifies, have to do with revealing the true nature of things. That is, not changing anything, but showing clearly what characteristics are present.
There are other places where the word and substance of salt is used for other meanings. It is talked about doing everything from disinfecting? a newborn (Ezekiel 16:4) to ruining good crop land (Job 39:6, Psa 107:34), so it does not seem that any assumptions can be made about the overall meaning of salt in the Bible. It was part of temple sacrifices (Lev 2:13) and it was what Lot’s wife was turned into (Gen 19:26).
If you take the natural qualities of salt all the way, then you have to admit that too much is not a good thing. Light, on the other hand, is typically best when bright for vision, putting aside issues of sunburn and dehydration, although everyone has experienced painful glare from too much light, too. Still, the metaphor appears to assume ideal application of both salt and light. It clearly tells us (or them) to let the light shine. Why? So that people will glorify the Father who is in heaven, because they see the good that comes from following him. It harkens to the verses that say the most important things are to 1) love God, and 2) love your neighbor as yourself. That covers everything about how God wants things to work. And for everyone’s mutual benefit, it seems.
Even though the phrase is used “if the salt has become tasteless,” based on other promises about God taking care of his own (Christians), I have to wonder if it is along the lines of seed falling on poor soil or people “falling short” of accepting the things of God, even when they very clearly know the choice they are making. Some people think they understand what God is offering, but haven’t truly comprehended it. They might not have really made the final choice yet. Others blatantly choose to refuse his life. Once they have done that, they are no longer good for anything except to be thrown out, by their own choice. I don’t claim to fully understand these issues of the heart, but it is made clear that repenting and believing are all that are necessary, a heart change follows, and God finishes the work of maturity in Christians (Phil 2:13).
Light is only talked about being “covered” in this passage. That kind of amuses me. Have you ever really tried to hide light? Light shows in darkness, even if people try to hide it. However, it does work better and is more useful if it is set out in the open. Don’t be afraid to let people see what God has done in you. It gives them one more chance to see what is really going on.
The trouble quickly becomes obvious, though. Not everyone likes what the light reveals about them and the truth of existence. And not all flavors are good, even when salted. Some people get angry when thus exposed. Or rubbed the wrong way? They often resort to blaming the light instead of acknowledging their own need for God. This is where it is useful to discuss how the Bible refers to “the world.”
The “world,” in Biblical terms, may be loved by God enough that he would send his son to die for them, but the way is narrow and few find it (Matthew 7:13-14). The broad way to destruction, followed by most of the mob, is somehow more appealing. At least until they get to the end.
The world is spoken of in two ways. It is sometimes used to mean the actual creation (Psa 89:11, Matthew 13:35); but based on this concept it is also a reference to those who live so completely connected to the fallen state of creation that they are in rebellion to God (Isaiah 26:9, Matthew 18:7, John 1:10). There is no call for us to “change” the world, as the world, in that second sense, is under the influence of the darkness of evil by default of refusing the light (1John 5:19, Rev 12:9). God has and will overcome it, but not by any efforts of ours. He saves individuals and puts them together as his church for now and they do good on this earth, but in the end “the world” will make one last effort to rebel in a great war against God (Rev16:14) The true nature of rebellious and prideful man has been revealed in each generation. There may be assorted advancements in technology, but the hearts of men remain unchanged unless they turn to God. There is no evidence of people becoming more enlightened spiritually as a whole. The only real and lasting enlightenment comes from knowing the true God.
All of this points to the fact that no one can change anyone else. Sometimes it seems everyone knows this except many proclaimed Christians. It is either incredibly ignorant or astoundingly arrogant to think you can change another person’s heart and intent. You may be able to offer advice (few people are particularly fond of advice) or provide incentives of social pressure or actual force, but each person’s heart is his own affair. The same forces yield different responses from different people. Some people abuse good opportunity. Others thrive in the face of hardship and mistreatment. It depends on them.
The last thing to address is what qualifies as “good works.” People have various opinions on this, affected by such things as their maturity, experience, knowledge, and specific circumstances. What is good for one person may very well not be good for another. Sometimes there is misinformation and mistakes are made about what is good in general or for one person. Sometimes people “do good” to make themselves feel better with relative laziness about understanding the true nature of the problem. One thing it doesn’t mean is exhausting yourself (love of oneself is presupposed and means caring for our own needs, too), or getting confused about our own limitations. God does not expect us to take care of all “the world’s” problems. The model seems more to be responsible for ourselves and our families (1 Thessalonians 4:11-12), and then help as we can. We can trust God to be God, and know that we are finite humans.
So, assuming we can consider that the passage in question also refers to us as being salt and light, be encouraged. We are not to be ashamed of the truth and love we know (as opposed to the self-righteous religiosity like the scribes and Pharisees had – verse 20). We are to be confident about letting our beliefs show, but knowing that it will sometimes lead to less than pleasant reactions by those who see and taste our inherited light and salt.