Rust testifies and eats flesh like fire
Here’s what it means
Hoarded wealth decays and becomes evidence against the unjust rich, pointing to consuming judgment.
Why the Bible says it this way
The Bible sometimes describes a thing, place, or idea as if it were a person so the point is easier to picture.
A helpful detail: Rust does not literally testify in court or eat flesh, but the moral evidence and judgment are real.