(Citation from Mishnah): If they damaged, the damager must pay [from Meitav].

Inference (R. Yosi): This teaches that a person who wounded his friend first, even though the victim countered and damaged him, [the first] is liable, for it says "u'Makeh Behemah Yeshalmenah.'' (It could have said Yeshalem. Rather, it says Yeshalmenah to teach that only the first pays.)

(R. Chanina): "Makeh Behemah Yeshalmenah.'' - he pays the decrease [and the victim keeps the carcass. It is as if it wrote Yashlimenah.]

(Bar Padyei): "Im Tarof Yitaref Yevi'ehu Ed [ha'Tereifah Lo Yeshalem]'' - up to the place [i.e. value of the Tereifah (carcass), he pays, but] the Tereifah, he will not pay (the victim keeps it).

(R. Nasa): We need R. Chanina's Drashah, and we need Bar Padyei's;

If we had only R. Chanina's Drashah, and not Bar Padyei's, I would say that for Hechsher Nezek (he enabled it to be damaged through not guarding it enough) he does not pay at all, and for damage from his own body, he pays the decrease. Therefore, we need Bar Padyei's Drashah;

If we had only Bar Padyei's Drashah, and not R. Chanina's, I would say that for Hechsher Nezek he pays the decrease, and for damage from his own body, he pays everything. Therefore, we need R. Chanina's Drashah and Bar Padyei's.

Version #1 (Rav Yehudah citing Shmuel): [RASHI 11a - the custom of judges is that] we do not estimate for a Ganav (covert thief, if the stolen object decreased in value) Gazlan (open robber) or borrower [they pay the full value, and keep the stolen or borrowed object. We estimate] only for Nezikin;

I (Shmuel) say that we estimate even for a borrower. Aba agrees with me.

Question: Who is Aba?

Answer: It is Rav, or Aba bar Avuha (Shmuel's father).

Objection (Rav Chisda): (Surely it is not his father.) Would he make the primary secondary (say the Halachah in his own name, and say that his father agrees)?!

Version #2 (Rav Yehudah citing Shmuel): We do not estimate for a Ganav, Gazlan or borrower, only for Nezikin. [The other] Shomerim are like Nezikin.

Question (Rav Yehudah, to R. Lazar): An extortionist (he forces people to sell), Ganav or Gazlan - do we estimate for them?

Answer (R. Lazar): We do not estimate for a Ganav or Gazlan.

Note: He did not answer about an extortionist! Perhaps he said only what he heard explicitly (e.g. in the name of Rav or Shmuel), but surely, the same applies to an extortionist.

Question: What is the source that we do not estimate for them?

Partial Answer (Rabah bar Mamal): "Chayim Shenayim Yeshalem'' - he pays live animals, and not dead ones.

Question: This teaches about Geneivah. What is the source for Gezelah?

Answer (Rabah bar Mamal): "V'Heshiv Es ha'Gezeilah Asher Gazal'' - [he returns] like he stole.