This tells me only of the second-tithe, of which Scripture speaks here. Whence do I derive the same for the other tithes? From "tithe shall you tithe."
Whence do I derive the same for the beast tithe? From "tithe shall you tithe."
R. Shimon b. Yehudah says: Whence do I derive that there is to be a beast tithe? From "tithe shall you tithe."
"which goes forth from the field": I might think that anything that grows in the ground, like issatis (a non-edible plant) and thorns, are subject to ma'aser; it is, therefore, written "Tithe shall you tithe … (23) and you shall eat."