Commentaire sur Péa 5:8

לכובעות – to make of them a kind of hat at the top, for such they were accustomed to making wreaths of ears of corn and to put them on the head.

One who binds sheaves into stack covers, stack bases, round stacks or regular stacks, he is not subject to the law of the forgotten sheaf [while binding].
[When bringing them afterwards] to the threshing-floor, he is subject to the law of the forgotten sheaf.
One who piles up the sheaves to make a stack, he is subject to the law of the forgotten sheaf.
[When bringing them afterwards] to the threshing-floor, he is not subject to the law of the forgotten sheaf.
This is the general rule: whoever makes the sheaves at the place which is the end of the work is subject to the law of the forgotten sheaf, [and afterwards when he takes] them to the threshing-floor, he is not subject to the law of the forgotten sheaf.
However, [one who piles up the sheaves] at a place which is not the end of the work, is not subject to the law of the forgotten sheaf; [and afterwards when he takes] them to the threshing-floor, he is subject to the law of the forgotten sheaf.
The status of a sheaf as “forgotten” is determined at the time when the processing of the sheaf is completed and it is ready to be threshed. Our mishnah comes to teach that the laws of the forgotten sheaf do not apply when he makes small piles of sheaves in order to later make them into a bigger stack or to bring them to the threshing floor. They only apply either when he makes the smaller bundles of sheaves into a large stack, or when he brings them to the threshing floor.
Section one: In this case, the worker makes the grain into small temporary sheaves while harvesting. If he forgets a sheaf at this point, it does not officially count as “forgotten” and it does not belong to the poor.
Section two: If he then proceeds to gather these small bundles of sheaves in order to bring them to the threshing floor and while doing so forgets one of them, it is considered to be “forgotten” and it belongs to the poor. This situation, and the previous one, will be illustrated in section six. When he makes the small bundles it is not yet “the end of the work” and therefore they are not yet subject to the laws of the forgotten sheaf. When he then takes them to the threshing floor, this is considered the end of the stacking/bundling work and they now are liable for the laws of the forgotten sheaf.
Section three: This is the opposite scenario. He makes a big stack of sheaves out in the field. There is no more work of stacking to be done, and hence if there is something forgotten at this point, it counts as a forgotten sheaf.
Section four: Henceforth, when he brings this stack to the threshing floor, it is no longer liable for the laws of the forgotten sheaf. This is illustrated in section five.
The general rule of the entire mishnah might be summed up thusly: the laws of the forgotten sheaf apply at the completion of the stacking/bundling process. Before and after this time if a sheaf is forgotten it does not count as a forgotten sheaf.

לכומסאות – they are not tall nor project above like hats, but are bent below so that they would be seen so much, as it states (Deuteronomy 32:34): “Lo, I have it all put away [Sealed up in My storehouses].”

ולחררה – reaped a little bit and made a temporary stack in the field, in order to roll the dough to make a thick cake baked on coals. Another explanation: There are those who harvest the grain and make a pile in one place until they are collected, and then they carry them to the place where they thresh the grain, and the place of the threshing is called a granary. And what they make a pile of on the ground is called stack covers, like the image of a hat which they place on a head, and what they make a pile of in a ditch in the field is called sheaves put at the bottom of a stack as foundation , like the language of (Deuteronomy 32:34): “Lo, I have it all put away,” and what they make a pile in a round heap like the image of the stone of a millstone is called a temporary stack in the field, on account that the temporary sheaf is round.

ולעמרים – he made small sheaves and he will end up making from two or three one sheaf.

אין לו שכחה – that is to say, what he forgot in the field at the time that he brings in from one of these places is not “forgotten,” as it is written (Deuteronomy 24:19): “When you reap the harvest in your field and overlook a sheaf in the field, [do not turn back to get it;]...,” just as there is reaping that has no reaping after it, so too carrying sheaves home, which have no other sheaves, which excludes those which have sheaves heaped up afterwards.

ממנו ולגורן יש לו שכחה – A person who brings from one of these places to the granary and forgot one heap of sheaves from these places, is considered “forgotten.”

המעמר לגדיש – and wants that they should remain in one place and there he will thresh them, there is something forgotten.

ממנו ולגורן – if he had his mind upon them and afterwards brought them to another place to thresh them, he has nothing forgotten.