I recently came across a criticism by atheists on the following verse:
You are the salt of the world. But if the salt should lose its taste, how can it be made salty again? It's good for nothing but to be thrown out and trampled on by people.
Apparently this is unscientific if we were to look at the reference of "salt" here as specifically dealing with the ionic bond of sodium chloride. Since Jesus is God, surely he would know about how his own creation operates?
In summary, electrostatic attraction results when atoms are ionized. The driving force behind ionization is the Octet Rule, which is the pairing of two atoms that have a tendency to form ions of opposite charges, where a mutually beneficial exchange of electrons can take place between them. Therefore, with respect to sodium chloride, we know that chlorine atoms are fairly electromagnetic, with an electronegativity of 3.16. However, sodium is not very electronegative (it's 0.93). This means that chlorine is very eager to accept an electron while sodium lets go of them. Sodium has the electron configuration of a noble gas. Chlorine also has the electron configuration of a noble gas. This drives the bonding behavior of the two atoms. It's the electrostatic attraction between them that causes this bond to form. But ionic bonds are not necessarily isolated connections between two atoms. When a mixture of ions like sodium and chloride get together, they can create a huge repeating structure known as a crystal lattice. This network of ionic bonds can stretch for billions upon billions of atoms that become so strong that the melting point of sodium chloride is 801° C. In fact, a recent 2013 paper showcased various compounds of sodium and chloride at different stable stoichiometries.
Therefore, salt cannot lose its saltiness, because sodium chloride is a stable compound. What then does Jesus mean? The answer is surprisingly simple: a citation of a well-known proverbial saying that actually affirms our modern scientific understanding of salt. Joshua ben Hananiah (1st century Rabbi) alluded to this proverbial saying when he was asked: "Can salt lose its flavor?”His response gives us the context of how people (and thus Jesus) understood the question, thus showcasing that people in the 1st century knew it was impossible for salt to lose its flavor, because he parallels the saying by responding with a question: "Does the mule [being sterile] bear young?"
Sterile mules can no more bear young than can salt lose its flavor. Thus, Jesus is using this expression to describe an equally impossible characteristic of his disciples. As they go out into the world as "salt," the proof of the reality of their profession is in the nature of their lives. True disciples cannot lose what makes them disciples because they have become changed persons, made new by the life of the kingdom of heaven. However, false disciples have only an external flavoring. They cannot be made "salty" again, because they never had that kingdom life in the first place.