(Mishnah): If one threw [something b'Shogeg] and remembered [that it was Shabbos] after it left his hand, and someone else or a dog caught it, or it burned in the air, he is exempt.

If one threw to wound a person or animal, and remembered [the Isur Shabbos] before it made the wound, he is exempt;

The general rule is, one is not Chayav Chatas unless he was Shogeg at the beginning and at the end;

If he was Shogeg at the beginning and Mezid at the end, or Mezid at the beginning and Shogeg at the end, he is not liable unless he was Shogeg at the beginning and the end.

(Gemara) Inference: Had it [not been caught or burned, rather,] landed, he would be liable, even though he remembered before it landed.

Question (Seifa): One is not Chayav Chatas unless he was Shogeg at the beginning and at the end.

Answer #1 (Rav Kahana): The Seifa discusses throwing a clasp on a rope (he holds the rope and could stop the clasp - therefore, if he remembers before it lands, it is as if he threw [partially] b'Mezid).

Objection: If he threw a clasp on a rope [and holds the rope] it is Agud b'Yado (he is exempt in any case)!

Answer: The case is, he intended to wound (Agud b'Yado exempts only regarding Hotza'ah).

Objection: The Mishnah already teaches that explicitly!

(Mishnah): If one threw to wound, and remembered before it made the wound, he is exempt.

Answer #2 (Rava): The Seifa discusses Ma'avir (carrying).

Objection: Surely, the general rule of the Seifa refers to throwing (for the entire Mishnah discussed throwing)!

Answer #3 (Rava): The Reisha discusses two cases:

If one threw and remembered after it left his hand, or even if he did not remember, and someone else or a dog caught it, or it burned in the air, he is exempt.

Answer #4 (Rav Ashi): The Mishnah is abbreviated, it means as follows

If one threw and remembered after it left his hand, and someone else or a dog caught it, or it burned in the air, he is exempt;

Had it landed, he would be liable.

This is if he later forgot again - but if he did not forget again he is exempt, for one is not Chayav Chatas unless he was Shogeg at the beginning and at the end.

(Mishnah): The general rule is, one is not Chayav Chatas...

(Rabah): If he was Shogeg while the object went two Amos, was Mezid during the next two Amos, and Shogeg during two Amos after that, he is exempt;

(Rava): He is liable.

(Rabah): Even R. Gamliel, who says that Yedi'ah (finding out) after half a Shi'ur has no effect, would exempt here - he obligates only when one completes the Shi'ur b'Shogeg, here he was Mezid at the end!

Question: What case does Rabah discuss?

He cannot discuss throwing - there, he is considered Shogeg (since even when he remembered in the middle, he could not stop it)!

Answer: He discusses Ma'avir.

(Rava): Even Chachamim, who say that Yedi'ah after half a Shi'ur exempts, would Mechayev here - they exempt only when one can refrain from completing the Shi'ur, he cannot!

Question: What case does Rava discuss?

He cannot discuss Ma'avir - there, also, he could refrain from completing the Shi'ur!

Answer: He discusses throwing.

(Rava): If one threw and it landed in the mouth of a dog or in an oven, he is liable. (He was Shogeg the entire time, or Mezid the entire time.)

Question (Mishnah): ...If someone else or a dog caught it, or it burned in the air, he is exempt.

Answer: That is when he did not intend for it to be caught or burned - Rava obligates when he intended for this.

Support (Rav Bivi bar Abaye - Mishnah): One can be liable four Chata'os and an Asham for one eating [slightly more than a k'Zayis] - a Tamei person who ate on Yom Kipur Chelev that was Nosar from Kodshim;

R. Meir says, if it was also Shabbos and he was Motzi the food in his mouth, he is also liable for Hotza'ah!

Chachamim: That Chatas is not for eating.

Question: It is not normal to be Motzi in the mouth!

Answer: Since he intends to eat, he makes the mouth a proper way to be Motzi

(Culmination of the support): Here also, since he intended for it to be caught or burned, he makes the recipient a proper place for Hanachah!

(Mishnah) Question: How much must one build to be liable?

Answer: One is liable for any amount of building, smoothing rocks, making a final blow with a hammer (Tosfos - to finish a Kli; Rashi - to quarry a rock) or hatchet, or drilling;

The general rule is - on Shabbos, one is liable for any Melachah that lasts (i.e. sometimes one does not do more than this).

R. Shimon ben Gamliel says, even one who bangs a hammer on an anvil [and not on the Kli being made] while making the Kli is liable, for this improves the final product (this will be explained).

(Gemara) Question: [If one builds] a tiny amount, what use does it have?

Answer #1 (R. Yirmiyah): A poor person digs a tiny hole to hide his Perutos (small coins);

Correspondingly in the Mishkan, people who sewed curtains dug tiny holes to hide needles.

Objection (Abaye): They would not do so, lest the needles rust!

Answer #2 (Abaye): A poor person makes legs (e.g. a tripod) for a small oven on which he rests a pot;

Correspondingly, if they needed to dye a bit more wool for curtains, they would make legs for a small oven on which to rest a small pot.

Objection (Rav Acha bar Yakov): In the place of wealth (Hekdesh), we do not conduct like paupers (from the beginning they prepared all materials in abundance)!

Answer #3 (Rav Acha bar Yakov): If one has a small hole in his house, he fills it;

Correspondingly, if a worm ate a hole in a board, they melted lead into it to fill it.

(Shmuel): If one sets a rock [in a foundation for a building] he is liable.

Question (Beraisa): If Reuven put a rock down and Shimon put the mud [to cement it in place], Shimon is liable.

Counter-question: [Sometimes] one is liable even without setting it!

(Seifa - R. Yosi): Even if he lifted it and put it on a row of rocks [to make a wall], he is liable.

Resolution: There are three levels of rocks:

Foundation rocks must be set and need dirt (one is not liable without this); intermediate rocks also need mud; upper rocks merely need to be placed.

(Mishnah): Smoothing rocks.

Question: For which Av is he liable?

Answer #1 (Rav): He is liable for building.

Answer #2 (Shmuel): He is liable for Makeh b'Patish.

(Rav): If one makes a hole in a chicken coop, he is liable for building;

(Shmuel): He is liable for Makeh b'Patish.

(Rav): If one drives a peg into the handle of a hoe (so the blade will not fall off), he is liable for building;

(Shmuel): He is liable for Makeh b'Patish.

The argument had to be taught in all three cases:

If we only taught about smoothing rocks, one might have thought that there Rav is Mechayev for building, for it is the normal way of building, but not for making a hole in a chicken coop;

If we only taught about a hole in a chicken coop, one might have thought that there Rav is Mechayev for building, for it is made for air and resembles building, but not for driving a peg into a handle;

If we only taught regarding driving in a peg, one might have thought that Shmuel would agree in the other cases, for they are [or resemble] the normal way of building.