Commentary for Bava Metzia 41:13

The gathering on the threshing floor - At the time of the gathering of the threshing floors; and their owners thresh [the grain] and carry off the main part and leave these over.

Great exertion - to collect them.

Smaller than that - If their scattering was in [an area] less than this.

Rav Ukva bar Ḥama said, "We are dealing with the gathering [of grain] on the threshing floor - One can be precise [and ask], why did Rabbi Yitzchak establish [the mishnah] to be specifically [a case of] a kav in four cubits and in the gathering [of grain] on the threshing floor? Let him establish it about a found object in general and [it being found] in the way of being dropped, and even more [than a kav]. And there is someone that answers that it is necessary for him, because he holds like Abbaye - since the law is like him - who says that abandonment without awareness is not [considered] abandonment. And hence our mishnah is not about a found object in general, but rather specifically [a case of] the gathering on the threshing floor - for it is a loss with awareness. And you should know it from that which we raise a difficulty from [the mishnah] to Abbaye (Bava Metzia 21b), and we do not find a resolution besides [the mishnah being a case of] the gathering on the threshing floor. And if you will say, "If so, how did it ask, 'if [it was] in the manner of being dropped, even more [than a kav would belong to the finder]" - one can say that the one that asks this held [like Rava. And Mar Ukava told him that it was specifically in the gathering on the threshing floor, and that is inevitable - since abandonment without] awareness is not [considered] abandonment. But this is not compelling in my eyes. For since we follow Abbaye, how could the gemara overtly raise a difficulty from the opinion of Rava - as the difficulty is [raised by] the gemara, so it [must be] stated according to the law (which is like Abbaye). And I can [answer] that it is saying it to [Rabbi Yitzchak], according to his explanation. As it thought that since he established [the mishnah] to be [in a case of] a kav in four cubits, it is implied that it is because they were scattered, and that he held like Rava. And because of this, they brought up a difficulty for him - [if it was] in the manner of being dropped, even more [than a kav would belong to the finder]; as [if the case was in] the manner of being placed, even less [than a kav would require announcement]. And one can also say that Rabbi Yitzchak came to make us understand the law of gathering on the threshing floor, and to say that our mishnah is speaking about any lost object, and even a loss about which one is aware - which is the [case of] gathering on the threshing floor when there is no more than a kav in four cubits. However, in general, if [it was] in the manner of being dropped, even more [than a kav would belong to the finder] - as since they were weighty, [the owner] would surely know [about their loss]. And that which we establish [the mishnah] later on according to Abbaye, to be about gathering [in the threshing floor] - that was before we knew the explanation of weightiness. But after we needed to answer about round cakes of figs (Bava Metzia 21b), that on account of their weightiness, [the owner] would know; we would not need to establish scattered grain only in gathering [in a threshing floor, but rather also in general. And that appears to be the opinion of the Rif, may his memory be blessed, who wrote this difficulty in his Halakhot (Rif Bava Metzia 12a) - "If [it was] in the manner of being dropped, even more [than a kav would belong to the finder]." And if it is not like this explanation, why did he write this? Is it not [otherwise] like the opinion of Rava, and we hold like Abbaye. And with this, the words of the rabbi, may his memory be blessed, are understood.