Explanation #1: It speaks where the wind on its own was not strong enough to fan the fire, because if it was, then even assuming that his blowing was sufficiently strong to fan the flames, why should he be Chayav ...

Reason: ... seeing as the fire would have spread and caused damage without him?

Conclusion: It must therefore be speaking where the wind was not strong enough. Consequently, if his blowing is sufficiently strong to fan the flames, he is Chayav ...

Reason: ... since he did everything ...

Source: Because it is like a case where, on Shabbos, one person is able to perform a Melachah and one person is not', in which case the latter is considered an assistant, which is not counted, as the Gemara explains in Perek ha'Matzni'a (Shabbos, Daf 93a & 93b).

Explanation #1 (cont.): ... whereas if his blowing is not strong enough to fan the fire, then he will be Patur, even if the wind is not strong enough either ...

Reason: Since one is only Chayav on account of Isho there where he did sufficient, without the help of the wind or anything else, that a regular wind is able to damage after his act has been concluded.

Proof: And that is implied in the words 'ha'Mav'ir es ha'Be'eirah' - that he made a fire by himself, that can subsequently damage with a regular wind.

Clarification (cont.): And the reason that he is Patur here is because without the fanning, it could not have caused damage, and the fanning which is the end result of the act, was not performed by the fanner alone.

Question: The Gemara then asks why he is Patur; Why, when he fans it with the help of the wind it is not considered as if he did it by himself ...

Source: ... like we find by Shabbos - where someone who winnows with the help of the wind is considered as if he did it on his own (and he is Chayav)? ...

Answer: ... to which Abaye replies that it speaks here - where he fanned it on one side, in which case, the wind will not normally help him, and therefore if it happens that it did, he is Patur ...

Reason: Because he cannot be expected to take into account the likelihood of the wind combining with his blowing, seeing as it is not common for that to happen, and he was not obligated to beware of it happening any more than a storm-wind. So the Ri explained.

Explanation #2: One can also explain that it speaks where he fanned it on one side, so that his fanning was not sufficient to fan the entire bonfire, nor was that of the wind

Explanation #2 (cont.): What therefore happened was that he fanned one side and the wind, the other ...

Reason: ... and had the bonfire been fanned only on one side, it would have gone out due to the weakness of the flame, and it is only because of the combination of the two halves of the bonfire that the fire gained strength and caused damage.

Conclusion: According to that, it is not comparable to someone who winnows and is helped by the wind, since there the wind did not help to fan what he fanned.

Clarification: This means that, if his fanning is sufficiently strong to flare up together with a regular wind, then he is Chayav - since it is considered as if he did it on his own ...

Clarification (cont.): But if not, where his fanning together with a regular wind is not strong enough, only together with a storm-wind that assisted him, then the fanner is Patur, since he did not need to take into account the arrival of a storm-wind.

Clarification: He did not blow into the fire in the way that the wind does, only he breathed hot breath into it to fan it ...

Clarification (cont.): .. and what the Gemara means is that, if his fanning is strong enough by itself to fan the flames, then he is Chayav, but if not, he is Patur ...

Implied Question: Even though he fanned them with the help of the wind...

Answer: ... he did not need to take into account the probability that the blowing of the wind will combine with his breathing, and succeed in fanning the flames ...

Answer (cont.): ... since it is not common for a blowing wind to combine with the hot breath of a person to assist him, seeing as in fact, they interfere with each other, even if they are both blowing on the same side ...

Reason: ... bearing in mind that the breath is hot and the wind is cold.

Clarification: When the wind that is assisting him causes the winnowing, it is considered a Meleches Machsheves, which is why he is Chayav for causing this winnowing, but it is not considered an act of winnowing on its own ...

Clarification (cont.): ... which is why here too, it is not called 'Mav'ir, only 'Goreim' (causing), and the Torah only renders liable 'Mav'ir' and not someone who causes a fire via an assisting wind.

Clarification (concl.): And in this way this G'rama in connection with fire is like all other types of G'rama by which the Halachah is 'G'rama be'Nizakin, Patur'.

Implied Question: And Mar bar Rav Ashi, who asks on the case of 'Raksa' (the shavings of flax which caused damage) in 'Lo Yachpor' (Bava Basra, Daf 26a & 26b) how it differs from 'Zoreh ve'Ru'ach Mesa'ayato', can hold like Rav Ashi here ...

Answer: ... since there it is talking about distancing the flax, which is considered 'his arrows', and which one is therefore Chayav to do.

Answer Extension: Even according to Rebbi Yossi, just as one is obligated to distance one's ladder from another person's dovecot, since it is considered 'his arrows'.

Implied Question: And even though the Gemara there considers it only G'rama, in that he Patur from paying ...

Answer: ... it is nevertheless forbidden and he is obligated to distance it from the other person's property.

Implied Question: And as for 'A spark that flies from under the hammer' which the Gemara considers Mazik (and not G'rama) ...

Answer: ... that is because he wants the spark to fly away, and he therefore bangs it with sufficient strength that when he has finished banging, it is able to cause damage with the help of a regular wind (as the Gemara explains in 'Lo Yachpor').

Refuted Answer: The Gemara did not want to establish the case where he banged it so hard that the spark went on to damage on in its own, without the help of the wind ...

Refutation: ... because then, it ought to have presented it, not together with Nizkei Eish, but with Nizkei Adam.

Inferred Halachah: It seems from here that if two people bring wood and fire and both fan it, that if the fanning of either one on his own is insufficient to ignite the wood, they are both Patur.

Question: However, this is difficult to understand!

Explanation #1: According to Rashi, this includes all living animals.

Explanation #2: But the Yerushalmi implies that it comes to include trees and things that are attached to the ground.

Yerushalmi: This is what the Yerushalmi says: 'If a haystack is unique inasmuch as it is detached from the ground, so too is one Chayav on whatever is detached from the ground (exclusively), therefore the Torah writes "O ha'Kamah".

Implied Question: Rabeinu Tam extrapolates from the fact that the Gemara mentions coming in before going out ...

Explanation #1: ... that it is referring to someone who is coming home from another town.

Additional Proof: And he also learns it from the fact that the Gemara at the beginning of Pesachim (Daf 4a & 4b) learns from Avraham Avinu that it will suffice to begin early performing a Mitzvah from the morning, since the Torah writes "And Avraham got up early in the morning" ...

Additional Proof (cont.): Now perhaps it is because on account of the Pasuk "Ki Tov" that he did not get up earlier? It must therefore be because the concept of "Ki Tov" is not applicable to someone who leaves his house.

Implied Question: And even though the Gemara here cites the Pasuk "And not one of you shall exit the entrance of his house until the morning", implying that it is also referring to someone who leaves his house?

Answer: That is because, since there it was a matter of life-danger, it is considered as if it was another town.

Conclusion: And this explains why the Gemara in the first Perek of Ta'anis (Daf 10b) cites the Pasuk "ha'Boker Or".

Explanation #2: The Ri maintains that one cannot extrapolate anything from (the inverted order) here, since it is the way of the Gemara to do this ...

Proof #1: ... as we find in Perek Bameh Madlikin (Shabbos, Daf 34b) 'Dusk is like the wink of an eye - the one comes in, the other goes out'.

Proof #2: And in Perek Osin Pasin (Eruvin, Daf 21a) the Gemara also says ' But a person clambers up (from the well) and clambers down'.

Conclusion: And it is perfectly in order to learn from "Vayashkem Avraham ba'Boker", since, on account of "ki Tov", it would not have been necessary to delay, seeing as he was going to perform a Mitzvah ...

Reason: ... and we have a principle that 'Sheluchei Mitzvah Einan Nizokin'.

Refuted Text: We do not have the text 'she'Ne'emar "le'Michmash Yafkid Keilav" ' ...

Reason: ... since that Pasuk - in Yeshayah, 10 - is written in connection with Sancheriv "Ba al Ayat Avar Migron, le'Michmash Yafkid Keilav".

Clarification: The Gemara is asking whether someone who saves himself from death is Chayav to pay damages.

Reason: The Pasuk writes "va'Yatzilah by both of them; by the field of barley - because they did not take it with the intention of paying lentils; and by that of lentils - because they did not take it from the person who acquired it.