Why did Jesus refer to humans as salt?
There may be possibly several reasons for this.
- Salt helps preserve food. Blessed is he who preserves the faith until the end.
- The faith in Christ is like a valuable pearl of great price. So too was salt in antiquity: it’s value was compared to gold.
- Salt adds flavour to food. Men who believe in God’s word recognize that man can not live by bread alone, but by every word that comes from the mouth of God.
First of all, before going into the question at hand, I would like to recount a little story about a someone giving a homily on this topic in French and he majorly messed up to the congregation by saying you the dirt soil of the earth! Vous êtes la sale terre! in French that could be translated as: You are the dirty soil of the earth! He meant to say: Vous êtes le sel de la terre! You are the salt of the earth. That a huge difference.
Roman soldiers were paid in salt!
Near Lausanne, in the foothills of the Alps, there are several centuries-old salt mines which are still operational today. In Roman times, and throughout the Middle Ages, salt was a valuable commodity, also referred to as "white gold." This high demand for salt was due to its important use in preserving food, especially meat and fish.
Being so valuable, soldiers in the Roman army were sometimes paid with salt instead of money. Their monthly allowance was called "salarium" ("sal" being the Latin word for salt). This Latin root can be recognized in the French word "salaire" — and it eventually made it into the English language as the word "salary."
Language is something we take for granted; we use it every day and could not live without it in today's world. However, as the example with the word "salary" shows, languages are not static but, rather, evolve. While the differences between American and British English are manageable, for example, reading Shakespeare in its original form poses some challenges — and reading the original Beowulf is almost impossible. -[From Salt To Salary: Linguists Take A Page From Science
At this time in history, not only was salt used to preserve food, but it was so valuable that that Roman Army was even paid their wages in salt. That gives a whole new meaning that someone is worth his weight in salt (not gold).
Salt in food
Salt is present in most foods, but in naturally occurring foodstuffs such as meats, vegetables and fruit, it is present in very small quantities. It is often added to processed foods (such as canned foods and especially salted foods, pickled foods, and snack foods or other convenience foods), where it functions as both a preservative and a flavoring. Dairy salt is used in the preparation of butter and cheese products. As a flavoring, salt enhances the taste of other foods by suppressing the bitterness of those foods making them more palatable and relatively sweeter.
Before the advent of electrically powered refrigeration, salting was one of the main methods of food preservation. Thus, herring contains 67 mg sodium per 100 g, while kipper, its preserved form, contains 990 mg. Similarly, pork typically contains 63 mg while bacon contains 1,480 mg, and potatoes contain 7 mg but potato crisps 800 mg per 100 g. Salt is also used in cooking, such as with salt crusts. The main sources of salt in the Western diet, apart from direct use of sodium chloride, are bread and cereal products, meat products and milk and dairy products.
In many East Asian cultures, salt is not traditionally used as a condiment. In its place, condiments such as soy sauce, fish sauce and oyster sauce tend to have a high sodium content and fill a similar role to table salt in western cultures. They are most often used for cooking rather than as table condiments.
In the Hebrew Bible, there are thirty-five verses which mention salt. One of these mentions Lot's wife, who was turned into a pillar of salt when she looked back at the cities of Sodom and Gomorrah (Genesis 19:26) as they were destroyed. When the judge Abimelech destroyed the city of Shechem, he is said to have "sown salt on it," probably as a curse on anyone who would re-inhabit it (Judges 9:45). The Book of Job contains the first mention of salt as a condiment. "Can that which is unsavoury be eaten without salt? or is there any taste in the white of an egg?" (Job 6:6). In the New Testament, six verses mention salt. In the Sermon on the Mount, Jesus referred to his followers as the "salt of the earth". The apostle Paul also encouraged Christians to "let your conversation be always full of grace, seasoned with salt" (Colossians 4:6). Salt is mandatory in the rite of the Tridentine Mass. Salt is used in the third item (which includes an Exorcism) of the Celtic Consecration (cf. Gallican Rite) that is employed in the consecration of a church. Salt may be added to the water "where it is customary" in the Roman Catholic rite of Holy water.
In Judaism, it is recommended to have either a salty bread or to add salt to the bread if this bread is unsalted when doing Kiddush for Shabbat. It is customary to spread some salt over the bread or to dip the bread in a little salt when passing the bread around the table after the Kiddush. To preserve the covenant between their people and God, Jews dip the Sabbath bread in salt. - Salt
Now if salt goes bad, it is worthless, both financially, as a preservative and as a addictive to make food taste better.
Thus we can see why Our Lord spoke thus about salt in reference to the verse Matthew 5:13:
13 “You are the salt of the earth. But if the salt loses its saltiness, how can it be made salty again? It is no longer good for anything, except to be thrown out and trampled underfoot.
Jesus desires his disciples to be the real salt of the earth and worth their weight in salt, so to speak! They must preserve the faith and share the Good News with all of mankind.