레위기 11:37의 주석

זרע זרוע means seed of any kind of seed-plant. The word זרוע is a noun (not a passive participle, when it would be punctuated ‎זָרוע), like (Daniel 1:12) "and let them give us of pulse — זֵרוֹעִים".

ZERA ZEIRUA’ (SEED OF SOWING). “Zera means ‘seed’ of any kind of seed-plant. Zeirua is the noun (‘sowing,’ ‘thing sown’), like the expression, and let them give us ‘zeiro’im’ (edible seeds) to eat.²⁶⁶Daniel 1:12. [And if aught of their carcass fall upon any seed of sowing which is to be sown] it is clean. This is to teach you that food is not fit and susceptible of becoming impure until water has once come upon it.” This is Rashi’s language.
Now Scripture mentioned above, of all the food which may be eaten, that on which water cometh [shall be unclean],²⁶⁷Verse 34. establishing the principle that foodstuff must first become susceptible to impurity [through coming into contact with water]. But there the Rabbis interpreted it to mean²⁶⁸Mentioned in Rashi ibid., on basis of Torath Kohanim. the foodstuff is not rendered impure through the medium of the interior of an [impure] earthen vessel, unless it was made susceptible of receiving impurity by being moistened by water. But here Scripture added that even from [contact with] the creeping things themselves, foodstuff does not become impure unless it was made susceptible [by water]. So it is explained in the Torath Kohanim.²⁶⁹Torath Kohanim, Shemini 11:8.
It is also possible to say that the expression of all the food which may be eaten.²⁶⁷Verse 34. refers to the things mentioned above — meat and various foods. But here He states that even seeds when taken out to be sown, can be rendered impure if they have become susceptible to impurity by being moistened by water. The reason for foodstuffs having to be made susceptible by water [before they can become impure], is that the uncleanness of [dead] creeping things and the other sources of impurity, attaches to foodstuffs in their state of moisteness, but not when they are dry. The Torah then, as an extra precautionary measure, declared impure those foods on which water had once come, although they have [subsequently] become dry, [if they were then touched by any of the sources of impurity], in order that the rule should not vary according to different standards. Now the law of making food susceptible of becoming impure applies also to the impurity [conveyed] by carrion, Scripture having mentioned it here for the reason we have stated above.²⁷⁰See Ramban at end of Verse 36 above.

אשר יזרע (בקרקע) טהור. Anything still connected to the earth is not subject to ritual defilement.

על כל זרע זרוע, “upon any edible seed that has been planted;” we learn from here that what has been planted as potential food will never be able to be ritually contaminated unless, after having been separated from the earth, it also has undergone a process of making it potentially fit to be ritually contaminated. In most cases, such as here, it means that it had become wet with the active or passive consent of the owner. Although we have already derived this rule from the verse (34) commencing with the words מכל האוכל, I would have had reason to think that such food is immune from contamination in the airspace of an earthenware vessel only. Alternately, previously the Torah only spoke about the kind of foodstuffs that are ready to be eaten in their present state, whereas in our verse here the Torah includes the seed, i.e potential food. As for the reason why these foodstuffs require a preparatory step approved by their owner before they are liable to become ritually contaminated, according to Nachmanides, the reason is that the dirt from these teeming creatures have a tendency to adhere to wet foodstuffs, (fruit) but not to dry ones. The Torah therefore decreed that wet foodstuffs are liable to be contaminated ritually. To the question why they should still be capable of becoming contaminated even if the owner had thoroughly dried these foodstuffs after they had become wet, the answer is that the sages never make their rules apply only partially, i.e. to some scenarios and not to others.

To be called “food.” Meaning: From that which it is written in the next verse: “If water was once placed on seeds and part of their carcasses fall upon them, they are unclean,” it implies that previously where it is written, “it remains [ritually] clean,” is dealing in a case where a part of their carcasses fell upon them before water came upon them. See Re’m where he cites the difficulties raised by Toras Kohanim and the Talmud: Why do we need a verse when it can be derived from that above (v. 34)? He brings the answers the Sages answered there. This raises a difficulty: This can be derived from (v. 38): “If water was once placed,” which implies that without water it cannot become impure! It appears to me that upon analysis of Scripture that first it says: “on any sowing seed that will be planted,” and then afterwards it says, “If water was once placed on seeds” where it mentions only “seeds.” Consequently, one could err and make a distinction between seeds that grow on their own without planting and those that are planted. I might think that when we say seeds are prepared to acquire impurity specifically through water being placed on them — that refers only to seeds that grew on their own without any action, but seeds that were planted and designated as food do not need require that they be prepared with water [in order to become impure]. Therefore, Scripture lets me know [that this is not true] (Divrei Dovid).

אשר יזרע, “which is to be sown;” which is to take root in the soil. This teaches that even seed which had been ritually impure will be transformed and be ritually clean once it has taken root. (Rash’bam.

טהור הוא HE SHALL BE CLEAN — Scripture by means of this and the following verse teaches you that it does not become fitted and proper to be termed food and therefore to be receptive of uncleanness, until water comes upon it.

זרע זרוע, the seed inside seed kernels. The word zerua is the singular mode of the word zeronim, זרעונים in Daniel 1,12, meaning “pulse.” [Alshich explains that it is a reference to raw pulse. At any rate this is the kernel containing the reproductive power of the plant in question. Ed.]