"the tithe" (ma'aser): This tells me only of clean tithe (that it may not be eaten outside of Jerusalem). Whence do I derive (the same for) ma'aser that is tamei? From (the superfluous) "your corn."
Whence do I derive (the same for) food that is purchased for money of ma'aser? From "your wine."
This tells me only of (such food that) is clean. Whence do I derive (the same for) what is tamei? From "and your oil."
R. Shimon says: From (Ibid. 26:14) "I did not eat in my mourning of it and I did not consume of it in uncleanliness," (which implies) whether I were tamei and it, clean or I clean and it, tamei — where is he exhorted (not to eat it)? I would not know, if it were not written "You shall not be able to eat in your gates the tithe of your corn and your wine and your oil," and, elsewhere (15:22) "In your gates shall you eat it, the unclean and the clean together," (which implies that normally it may not be eaten together).