RobH_en_tn/isa/13/12.md

I will make men more rare than fine gold

Why there will be so few people can be stated clearly. AT: "I will cause so many people to die that living people will be more rare than fine gold" (See: rc://en/ta/man/translate/figs-explicit)

men more rare than fine gold ... mankind harder to find than the pure gold of Ophir

These two phrases mean basically the same thing. (See: rc://en/ta/man/translate/figs-parallelism)

pure gold of Ophir

Ophir was the name of a place where there was pure gold. (See: rc://en/ta/man/translate/translate-names)