Midrasz do Powtórzonego Prawa 24:6

(Devarim 24:6) "One shall not take as a pledge the nether millstone nor the upper millstone": Whence do we derive (the same for) all things (that process food)? From "for it is a soul (i.e., a life) that he takes as a pledge." If so, why mention (only) nether millstone and upper millstone? Just as these are distinct in being implements performing one task, for each of which in itself one is liable, so, one is liable for all such implements.