(Mishnah - R. Elazar): A Mu'ad cannot be guarded. It must be killed.

Question (Rabah): What is R. Elazar's reason?

Answer #1 (Rabah): He learns from "and he will not guard it" (after becoming Mu'ad), it cannot be guarded.

Question (Abaye): If so, he should also expound "and he will not cover (a pit)" - it can no longer be covered!

Suggestion: Perhaps indeed, this is true!

Rejection (Mishnah): If he covered a pit properly and an animal fell in and died, he is exempt.

Answer #2 (Abaye): R. Elazar holds like R. Nasan.

(Beraisa - R. Nasan): "Do not put blood in your house" forbids raising a wild dog or erecting a rickety ladder in one's house.

(Mishnah): If an ox gored a cow, and a dead calf is near the cow, and we do not know if the calf was born before the goring (and died by itself), or after the goring (and died due to the goring), the ox pays half- damage for the cow, and quarter-damage for the calf.

Similarly, if a cow gored an ox, and a calf is near the cow, and we do not know if the calf was born before or after the goring, we collect half-damage for the ox from the cow, and quarter-damage from the calf.

(Gemara - Rav Yehudah): Our Mishnah is like Sumchus, who says that when in doubt, we split the money;

Chachamim argue and say, the great general rule in monetary matters is ha'Motzi me'Chaveiro Alav ha'Re'ayah (the one who wants to collect must bring proof).

Question: Why must they say 'this is a great general rule in monetary matters'?

Answer #1: This includes even when the victim makes a definite claim, and the damager is unsure.

Answer #2: This teaches like Shmuel taught (below).

(Rav): If Reuven sold an ox to Shimon, and it was found to be a gorer, the sale is mistaken (and therefore void).

(Shmuel): Reuven can say, I sold it to you to slaughter (the sale is valid).

Question: Let us see whether Shimon buys oxen for plowing or for slaughter!

Answer: The case is, he buys for both.

Question: Let us see if he paid the price of a plowing ox or an ox for slaughter!

Answer: The case is, the price is the same for both.

Question: If Reuven has nothing else to give Shimon in place of the money he owes, he may give him the ox!

Answer: The case is, Reuven has other money.

Rav says that the sale is mistaken. We follow the majority. Most people buy oxen for plowing;

Shmuel says, he can say 'I sold it to you to slaughter.' We follow the majority only in Isurim;

In monetary matters, ha'Motzi me'Chaveiro Alav ha'Re'ayah.

Support (for Rav Yehudah - Beraisa - Sumchus): If an ox gored a cow, and a dead calf is near the cow, and we do not know if the calf was born before or after the goring. The ox pays half-damage for the cow, and quarter-damage for the calf;

Chachamim say, ha'Motzi me'Chaveiro Alav ha'Re'ayah.

(Rav Shmuel bar Nachmani): Chachamim learn this principal from "whoever has a claim Yigash (will approach) them (Aharon and Chur)" - we read this, Yagish (he will bring (proof)) to them.

Objection (Rav Ashi): Why must we learn from a verse? Logic dictates this!

Rather, the verse teaches like Rav Nachman.

(Rav Nachman): We first listen to the one who claims that he should collect (and he collects before we hear the other party's claim) - "whoever has a claim Yigash to them" - Yagish (he will bring his claim (first)).

(Chachamim of Neharda'a): Sometimes we listen to the defendant's claim first, e.g. if his property is declining in value.

(Mishnah): Similarly, if Reuven's cow gored Shimon's ox...

Question: Why does he pay half-damage (from the cow) and quarter-damage (from the calf)? He owes only half- damage!

Answer #1 (Abaye): When the Mishnah says half-damage, it refers to half of what he must pay, i.e. quarter-damage. When the Mishnah says quarter-damage, it means, eighth-damage.

If Reuven owns also the calf, he must pay half-damage no matter when the calf was born. The case is, Levi owns the calf.

Version #1: If Shimon first demanded payment from Reuven, Shimon can say, your cow damaged my ox. You (alone) owe me half-damage, unless you can prove that the calf (was already born and) was a partner in the damage.

The case is, Shimon first demanded payment from Levi. (A Vadai partner in the damage would pay half of half-damage, i.e. quarter damage. Shimon gets only an eighth because we are unsure whether the calf was a partner.) Now Reuven can say 'you showed that you believe that there was a partner in the damage, so I need pay only half the half-damage.)

Version #2: Even if Shimon first demanded payment from Reuven, Reuven can say, I believe that there was a partner in the damage. I will pay only half the half- damage, unless you bring proof otherwise. (end of Version #2)

Objection (Rava): The Mishnah does not say quarter- damage and eighth-damage. It says half-damage and quarter-damage!

Answer #2 (Rava): Really, Reuven owns also the calf. The Mishnah means that if the cow is here, the full half- damage is collected from the cow;

If the cow is not here, quarter-damage is collected from the calf.