Succah, Chapter 4, Mishnah 7. The Mishnah continues the subject we dealt with in the previous mishnayos: the order of the service in the Beis HaMikdash on Hoshana Rabbah, the last day of Succos before Shemini Atzeres.
The words of the Mishnah: "Miyad hatinokos shomtin es lulveihen v'ochlin esrogan" - immediately the children slip off their lulavim and eat their esrogim. Two ways of explaining this were stated:
The first explanation - "miyad" in its plain sense:
After they finished circling the altar seven times (and according to one opinion, with the palm branches), immediately upon taking leave of the altar the children would untie their lulavim from the binding that held them together, and would eat their esrogim. The adults, however, did not eat the esrog for the entire day, because it had been designated for the mitzvah, and once it was designated for the mitzvah it remains muktzeh the whole day and may not be used.
The second explanation - "miyad" from the word yadayim, hands:
Some explain that the meaning is not "immediately" in the sense of time, but rather that the adults would slip the lulavim out of the children's hands and eat their esrogim. The reason: the children's esrogim were not designated for a full mitzvah, since they are not used for an actual mitzvah obligation but only for chinuch, education, and therefore eating them was permitted.
The Mishnah teaches us, as Rashi explains, that there is no element of theft in this. It was not like taking an object from a child's hand without permission, but rather a way of rejoicing: an accepted custom as part of the joy of the day, to show that they had completed the mitzvah.
In summary: in this Mishnah we learned what was done at the conclusion of the circuits around the altar on Hoshana Rabbah - slipping the lulavim out of the binding and eating the esrogim - and the two ways of explaining the word "miyad": in its plain sense, that the children did this themselves immediately upon taking leave of the altar, or from the word yadayim, hands, that the adults took them from the children's hands, since the esrogim of minors are not designated for a full mitzvah, and there is no theft in this but rather a way of rejoicing.