Mathew 5:13, “Ye are the salt of the earth: if the salt have lost his savour (saltness – Mark 9:50) . . . It is thenceforth good for nothing, but to be cast out, and to be trodden under foot of men.”
Salt, Sodium Chloride, has a myriad of uses. The Morton Salt Company has listed more than 1400 uses of salt. Salt is used to preserve food (historically, this may well be its most common and most important use). Salt is used to season food. Humans and animals require some salt in their diets to digest certain nutrients such as proteins. Salt prevents rapid, excess water loss. Salt is used to melt ice and prevent water from freezing. Salt can be used to kill weeds along a fence line. Salt also can be used to prevent the spread of bacteria.
But, imagine if you purchased salt for one of the above purposes, and that salt did nothing. You might well throw it out into the street to be trodden under the foot of men.
This is what you might do “if the salt lost his savour (saltness).” But, the skeptic objects just here, “salt does not lose savour or saltness. How then does one explain this passage?” good question!
Understand that salt, though common to twenty-first century America, was extremely treasured in the ancient world, and even today in other parts of the world. Britannica says, “Cakes of salt have been used as money in Ethiopia and in Tibet. In the Roman army, an allowance of salt was made . . . Salarium, from which the English word ‘salary’ is derived (Vol. 16, p. 193). Today we still use the saying, “He is worth his salt.” This saying has reference to the Roman ‘salary.’ With this in mind, listen to John Hudson Tiner; He writes, “Salt was so valuable in Bible times that people added clay to make it last longer. In the Bible, the salt which lost its saltiness . . . was salt added with clay or sand added. The clay was all that remained after the salt had been washed out.” (Exploring the World of Chemistry, p. 72). H. Leo Boles explains it this way, “The salt of the ancient world was not purified as it now is; hence it retained all of the less soluble compounds of lime, iron, and other things which occur in all natural salt water; therefore it contained a large quantity of insoluble substance which remained . . . after the real salt had been dissolved out of it.” (G.A. Commentary, p. 127).
Either way, the point in the passage is the same. We, like salt have a function. We, like salt, are to be preservers in this earth. If we cease to function as expected, we are “good for nothing, but to be cast out.”