Volume 3, Book 34, Number 314:
Narrated Abu Musa:
Allah’s Apostle said, “The example of a good companion (who sits with you) in comparison with a
bad one, is I like that of the musk seller and the blacksmith’s bellows (or furnace); from the first you
would either buy musk or enjoy its good smell while the bellows would either burn your clothes or
your house, or you get a bad nasty smell thereof.”