(Devarim 23:6) "If you come into the standing corn of your neighbor": I might think (that the verse speaks of) any man (who passes the standing corn); it is, therefore, written (Ibid.) "but you shall not lift a sickle" — when you are lifting a sickle (as a worker) upon your neighbor's standing corn.
"your neighbor": but not a gentile. "your neighbor": but not the Temple.
"you may pluck the ears with your hand": but you may not cut them with the sickle.
"but you shall not lift a sickle" (for yourself, even) when you lift a sickle upon the standing corn of your neighbor.