A somber tone to this one.
This is what happens when you ponder idioms, common sayings and phrases too much.
“Neither snow nor rain nor heat nor gloom of night stays these couriers from the swift completion of their appointed rounds.”
These words, a translation from ancient Greek describing the Persian courier service c. 500 BC, are inscribed on the James Farley Post Office in New York City. Through the years these words, in whatever form you remember them by, has in many minds become associated with the US Postal Service itself, though the words originally had no relation to them.