What does the term "rain to fire" mean?

Question

Where did it originate, what is it applicable to?

Answer 1

I haven't heard of this expression. I have heard of "rain of fire", though, as in a battle situation where there are so many bullets that they equate to the drops of water in a rainstorm. This can then be applied to other situations, like getting through a crowd of people hurling abuse like a rain of fire.