QUESTION: Aba Elazar ben Gamla teaches that the verse compares the Halachos
of Terumah to the Halachos of Terumas Ma'aser, and it compares the Halachos
of Terumas Ma'aser to the Halachos of Terumah. We learn from this that just
as Terumah (i.e. Terumah Gedolah) may be separated by estimating the amount
(one-fiftieth) that one is required to separate, so, too, Terumas Ma'aser
may be separated by estimate, without actually measuring the amount
(one-tenth).
RASHI explains that the one-fiftieth of one's produce that the Rabanan
required that one separate as Terumah Gedolah may be separated based on a
rough estimate, because even if one mistakenly separates too little, he has
fulfilled the Torah requirement. The Torah requires that only a single grain
of wheat be separated.
Aba Elazar ben Gamla is teaching a Halachah mid'Oraisa regarding the
separation of Terumas Ma'aser that is derived from this verse. If,
mid'Oraisa, even one grain of wheat is enough for Terumah Gedolah, then
there is no concept of estimate with regard to Terumah Gedolah! How, then,
can he say that "just as the Torah permits estimating for Terumah Gedolah,
it permits estimating for Terumas Ma'aser?" Terumah Gedolah has no Shi'ur,
and thus estimating is irrelevant, while Terumas Ma'aser does have a
specific Shi'ur mid'Oraisa!
ANSWER: Rashi seems to be learning that even mid'Oraisa a person must
separate, l'Chatchilah, a certain amount of his produce as Terumah, and it
does not suffice l'Chatchilah to separate just one grain. Only b'Di'eved
does a single grain exempt the rest of the produce. It does not make sense
that the Torah would permit separating a single grain, l'Chatchilah, for
Terumah, because the purpose of Terumah is to provide a livelihood for the
Kohanim; if everyone gives the Kohanim only one grain, that will not provide
any sort of livelihood for them! It must be that the Torah requires that a
larger Shi'ur be separated. However, the Torah does not specify what amount
one should separate l'Chatchilah as Terumah. Rather, in such a situation, it
must be that the Torah gave over to the Chachamim the responsibility to
determine a fitting Shi'ur, and that Shi'ur will be considered a Shi'ur
mid'Oraisa (see Chagigah 18a; RAN in Yoma 73a; TOSFOS in Yoma 79b, DH Lomar
Lach). Therefore, even though the Chachamim said that the Shi'ur of Terumah
is one-fiftieth, nevertheless that Shi'ur is considered a Shi'ur mid'Oraisa;
the Chachamim merely revealed to us what the Shi'ur d'Oraisa is.
(TOSFOS and the TOSFOS HA'ROSH are also bothered by the usage of the word
"estimate" with word to Terumah Gedolah. They propose a forced answer,
saying that the word "estimate" really does not apply to Terumah, but only
to Terumas Ma'aser. Aba Elazar is just deriving that just as one may add as
much as he wants to Terumah Gedolah, he may also add as much as he wants to
Terumas Ma'aser. Rashi is avoiding their question by explaining that there
is a Shi'ur mid'Oraisa for the amount of Terumah Gedolah that one must
separate l'Chatchilah.)