The Gemara continues its discussion about an Arev Kablan and lists the
different expressions that are valid for a guarantor to use to accept upon
himself an obligation of Arvus or an obligation of Kablanus.
(a) RASHI (Gitin 49b, DH b'Kablan; see also RASHBAM earlier in Bava Basra,
beginning of 47a) explains that the word "Kablan" denotes that the Arev
*received* ("Kibel") money or an object on behalf of the borrower. Since the
object passed through his hands, he has accepted a greater obligation
towards the lender. TOSFOS (Gitin 49b, DH b'Kablan) explains that according
to Rashi this is the meaning of "Kablan" whenever the Gemara discusses the
concept.
In the case of a normal loan, it is clear that the Arev can become a Kablan
by accepting the money that the lender gives to the borrower. However, the
Gemara later (174b) and in Gitin (49b) says that when a person becomes an
Arev for the payment of a Kesuvah, he is not obligated to pay even if the
husband has no money with which to pay (as per the reason that the Gemara
here gives later). If he becomes an Arev *Kablan* for a woman's Kesuvah,
then he does become obligated to pay. How, though, does the Arev Kablan
obligate himself in the case of a Kesuvah according to Rashi? In the case of
a Kesuvah, the woman has not yet received her Kesuvah, and she is not giving
anything to the Arev Kablan in order to obligate him to pay the Kesuvah when
the time comes. How, then, can a person become a Kablan for a Kesuvah?
Rashi explains that one can become a Kablan for a Kesuvah in a case where
the husband designates certain Metaltelin items in his possession for the
payment of the Kesuvah, and he gives them to his wife to hold until the time
comes to collect the Kesuvah. If the wife then hands over those Metaltelin
to an Arev in order for him to return them to her husband, then the Arev
becomes an Arev Kablan.
In contrast to Rashi's definition of an Arev Kablan, our Gemara gives
different criteria for defining the difference between a Kablan and an Arev.
The Gemara says that when a person asks the lender to accept him as a Kablan
for the loan, he uses a different wording ("go give him money") than the
wording used by an Arev ("lend him money"). Tosfos explains that Rashi
understands that a Kablan requires *both* a different wording, *and*
physically accepting the money of the loan for the borrower. (See also
Insights to Gitin 49:2.)
(b) The RASHBA and RITVA in Gitin explain that a Kablan becomes a Kablan
simply because of the wording that he uses when he accepts the Arvus. This
follows the simple reading of the Gemara here in Bava Basra. It is not
necessary for him to physically accept any money or object. The reason he is
called a Kablan is because he has accepted (Kibel") responsibility to pay
back the loan. If he physically accepts the loan itself, then he has a much
greater obligation than an Arev Kablan, and the lender may collect *only*
from him and not from the borrower (as the Gemara here says).
The RASHBAM (173b, DH Kablanus) seems to have retracted what he wrote
earlier in Bava Basra and sides with these Rishonim.
(c) The TOSFOS HA'ROSH and the RASHBA (in the name of Tosfos) in Gitin
compromise and explain that, normally, a person becomes a Kablan based on
the wording that he uses, and not because he physically accepts the loan.
However, the wording alone is not enough to make a person a Kablan for a
*Kesuvah* (because he is not causing the wife any loss by accepting
responsibility, since she has not handed over any money as a result of his
promise to pay back), which is the case being discussed in Gitin. Therefore,
in order to become an Arev Kablan for a Kesuvah, it is necessary for the
wife to have received Metaltelin that were designated for the payment of her
Kesuvah and to return them based on the promise of the Arev. Only then does
one become an Arev Kablan.