Matthew 5:13-16 (AD 28)
Salt is not limited to a single function, so there is no singular meaning. Rather, there are about ten uses, so if we are to be like salt, there should be many ways we make a positive impact Given the context, the are probably three uses of salt that are most in view:

- A preservative: before fridges were invented salt was necessary to use for preserving meat
- Associated with purity (Exodus 30:35; 2 Kings 2:19-22)
- Flavour-enhancer – hence the makers of microwave meals put in loads of it to compensate for the lack of natural flavours! (Colossians 4:6)
Salt, i.e. sodium chloride can NOT become less…sodium chloridey… However, ‘salt’ to a first century Jew was an extremely impure or crude compound that contained salt; a rock with salt in it rather than table salt, which is what you get when all the rock is out of the way. That’s fine until the rock comes into contact with water, at which point the salt dissolves, leaching out of the rock. Then, the rock that was referred to as ‘salt’ has now lost its saltiness, and furthermore given what we know about how it lost that saltiness, it cannot be made salty again.
What you are left with is a worthless piece of rock, “no longer good for anything, except to be thrown out and trampled underfoot” (v.13). You might not immediately notice if you look at the salt rock that all the sodium chloride has gone, but as soon as you try to use it, it will be obvious.
This wasn’t Jesus making a dire threat about a failure to persevere in faith. Just as he offered a reassurance to professing Christians that their holy and useful lives will bring blessing, and along with it persecution, here he pointed out that you can’t have the blessing, without persecution, by avoiding your holy and useful life. Why? Because holy and useful living is a preservative (of life), a purifier (from sin) and a flavour (usefulness) enhancer.
The way you live in the world saves lives by highlighting sinfulness, pointing to God, demonstrating grace and providing a model for people to follow. And if you are NOT doing those things, you might call yourself a Christian because at first glance you might seem like one, but close contact would reveal that you are not what you claim to be. That is, you are impure salt from which the sodium chloride has dissolved out.
To maintain that salt-like quality we must act and speak like Christians, according to the pattern laid down by Jesus. For example are there situations in which you regularly or easily get drawn into gossip? Then maybe you need to avoid those situations, even if you feel ostracised as a result.
There is a balance. On the one hand we are not to shun everyone who behaves poorly. On the other hand, “Do not be misled: Bad company corrupts good character” (1 Corinthians 15:33). It’s naïve to think our friends don’t influence us – that’s why God encourages us to have godly friends. On the other hand, if salt just hangs out with salt, there’s no point in it being salt. So we are to be among and engaged with those who don’t love God, talking to them about their need for God and showing them what loving God looks like.
Striking that balance requires godly wisdom, humility, accountability, compassion…and hard work.
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Footnote:
The other contemporary uses/significances of sodium chloride were:
- Associated with the destruction of impurity (Deuteronomy 9:23; Judges 9:45)
- Creates thirst
- Added to sacrifices (Leviticus 2:13)
- A sign of loyalty (Numbers 18:19)
- Fertiliser (Luke 14:34-35)
- Symbolic of wasteland (Deuteronomy 29:23; Judges 9:43)
- Used in cleaning newborn babies(!) (Ezekiel 16:4)