Commentary for Avodah Zarah 83:16

Yes, I know that this source is a bit gross and quite strange as well. Why does the priest need to know if it is male or female? While it is true that there are different periods of purity and impurity for male or female births (see Leviticus 12), is this slave Jewish such that she would observe these laws? Why doesn’t the priest know that he should not look into the pit to see because that would make him impure? In any case, there seems to have definitely been a source of impurity placed into the pit. The doubt is over whether it is still there. And again, a doubt does seem to set aside a certainty.

The Talmud solves the problem again in two ways.
First of all, we could say that there was a doubt whether or not she even threw away a fetus, or whether it was a very early miscarriage, which would not defile. This is a case of a doubt setting aside another doubt.
Second, we could say that the weasel or marten definitely dragged it away, since there are so many such animals in this area. This is a case of a certainty setting aside another certainty.
But as R. Yohanan said, a case of doubt does not set aside a certainty.

According to the mishnah, an Israelite cannot annul an idol belonging to an idolater. But why should these fragments not be permitted if he breaks them? Why not consider this to be like an idol that broke on its own? This proves, to R. Yohanan, that an idol that broke on its own is not permitted.

Abaye tries to resolve the difficulty by saying that the Israelite only defaced the idol, he did not actually smash it.
The problem with his resolution is that there is a mishnah that says that defacing an idol is sufficient to annul it.
The Talmud answers that if an idolater defaces it, it is annulled. But if an Israelite defaces it, it is not annulled. However, if an Israelite smashes the idol, then it is annulled, just as it would be if it broke on its own.

According to Rava, theoretically an Israelite can annul the idol by defacing it. However, the rabbis did not allow this lest when he picks the idol up, it comes into his possession. An idol owned by a Jew can never be annulled.
Rava is really only arguing with Abaye. As far as our larger argument goes, both Abaye and Rava agree that if a Jew were to smash the idol of a non-Jew, it would be annulled. So too, according to Resh Lakish, if the idol broke on its own.

Again, we read a baraita which says that even if an Israelite breaks up a statue of Mercury (which was originally composed of stones) and uses it to pave a road, the stones and everything they were used to build is prohibited. This is a difficulty against Resh Lakish.
The Talmud resolves this by again citing Rava’s statement. In principle these stones were annulled because the idol was broken. However, we don’t allow people to use them lest the Jew come to own the idol, in which case it can’t be annulled. But if an idol broke on its own, it is annulled.

The baraita quoted here discusses an idol that had pieces chipped off of it. If the idolater does this, then the status of the idol depends on the idolater’s intention. If he simply wants to use pieces of the stone for some other purpose, then he is no longer treating the idol with any sanctity. The idol has been annulled and a Jew can now make use of it. But if he chips a piece off to improve the idol, then the idol has not been annulled.
A Jew cannot annul idols. Therefore, it does not matter why he chipped off a piece.
But again, this is a difficulty against Resh Lakish. Why shouldn’t we consider this like an idol that broke on its own?
Resh Lakish can again solve this according to Rava’s statement. If a Jew chipped off a piece of the idol of a non-Jew, it should be annulled. But we consider it not to be annulled, lest the Jew come to possess the idol, and the idol of a Jew can never be annulled.

The baraita contains a dispute over whether an idol can be destroyed by a Jew by grinding it up to powder. Rabbi Yose finds this acceptable, but the other rabbis worry that one may end up deriving benefit from the idol by doing this. Therefore, they demand that the idol be destroyed by throwing it into the sea.
But again, we could ask. If, as Resh Lakish claims, even an idol that broke on its own can be used by a non-Jew, then why shouldn’t grinding it up be a valid form of annulment, in which case any benefit derived would not be a problem.
Again, the solution follows Rava. He cannot annul it that way lest he come to acquire it.

An idolater can annul an idol, but a Jew cannot. So if we do not know who cut the dragon idol’s head off, the idol is permitted. In cases of doubt, the law is lenient. But if we know a Jew cut the head off, the idol remains prohibited. This is essentially the same difficulty against Resh Lakish as we saw above. Why isn’t this considered an annulled idol, like the case of an idol that broke on its own?
Again, the Talmud solves this according to Rava. Technically, the idol is annulled, but we do not permit it lest the Jew come to own the idol, in which case the idol can never be annulled.

An Asherah is a tree that is worshipped. One may not derive any benefit from such a tree. R. Yose says that one may not plant under such a tree, because that would be taking advantage of the falling leaves as fertilizer. But again, why not consider the leaves to be like an idol that breaks on its own. After all, that is essentially what happened to the tree.
In this case we cannot consider the leaves to be annulled because the tree is still standing and nothing has happened to it. Unlike an idol that breaks, no one would say that the tree has broken just because some leaves fell off.