The Torah in Parashat Kedoshim (19:27) introduces the prohibition of “lo takifu pe’at roshekhem,” which forbids “rounding” the hair of a man’s head by removing the sideburns, the hair that grows alongside the ears.
The Gemara in Masekhet Makkot (20b) cites a berayta stating that when somebody shaves a person’s sideburns, both the “makif”’ and the “nikaf” – meaning, the person who performed the act, and the one to whom it was done – are liable to punishment. The question is then raised as to how the nikaf could be liable for an action performed by another person, and the Gemara brings three explanations offered by various Amoraim. The first posits that this berayta follows the minority opinion of Rabbi Yehuda, who maintains that a violator is liable to punishment even in the case of a “lav she-ein bo ma’aseh” – a prohibition transgressed passively, through inaction. According to Rabbi Yehuda, one who has his sideburns removed is liable to punishment for violating “lo takifu” even though he performed no action in violating this command. Hence, one possibility of explaining the berayta is to claim that it reflects Rabbi Yehuda’s position. A second possibility, proposed by Rava, is to explain that the berayta actually refers to the case of somebody who removed his own sideburns, and it means that he is liable to two sets of lashes – one for removing sideburns, and another for having his sideburns removed. The third view is that the berayta speaks of a case where the individual whose hair was cut assisted the barber through some action, and so they are both liable to punishment, as both were actively involved in this forbidden act.
The Rambam (Hilkhot Avodat Kokhavim 12:1) follows the final view, and rules that if a person removes somebody else’s sideburns, the barber is liable to punishment, but the other is not unless he was actively involved. The Ra’avad clarifies that nevertheless, although the one whose sideburns are removed is not liable to punishment if he did not assist the process in some way, he has transgressed the Biblical prohibition of “lo takifu” by virtue of his having allowed this to happen. A number of commentators to the Rambam’s Mishneh Torah, including the Mabit, in his Kiryat Sefer, and Rav Avraham de Boton, in his Lechem Mishneh, understood that the Rambam concurs with the Ra’avad’s view. According to this opinion, one who allows somebody to remove his sideburns transgresses this prohibition even if he performs no action to facilitate the removal of his sideburns, notwithstanding the fact that no liability to punishment is incurred without some action being performed.
Rav Yosef Karo, however, in his Kessef Mishneh commentary, disagrees. He contends that in the Rambam’s view, one whose sideburns are removed by another person does not violate Torah law unless he plays some active role. The Noda Bi-yehuda (Mahadura Tinyana, O.C. 76) suggests drawing proof to the Kessef Mishneh’s position by contrasting the Rambam’s comments in this context and his comments elsewhere, in Hilkhot Chameitz U-matza (1:3). There the Rambam writes that if one possessed chameitz before Pesach and did not eliminate it before the onset of the holiday, then he has violated the prohibition against owning chameitz on Pesach, though he is not liable to punishment, since he did not perform any forbidden action. In that context, the Noda Bi-yehuda observes, the Rambam makes it clear that the Torah prohibition is transgressed despite the fact that the violator is not liable to punishment since he performed no action. It stands to reason, then, that if the Rambam felt the same about one who passively allowed his sideburns to be removed, then he would have clearly stipulated as such, just as he did in regard to one who failed to eliminate his chameitz. The fact that the Rambam did not clarify this distinction would seem to indicate that in his view, one who remains entirely passive while his sideburns are removed does not violate the Torah prohibition.
The Noda Bi-yehuda acknowledges that the Gemara’s discussion in Masekhet Makkot, noted above, at first appears to indicate otherwise. After all, the first view cited by the Gemara explains the berayta as reflecting Rabbi Yehuda’s opinion that one is liable to punishment for Torah violations even if they are committed passively. This certainly seems to suggest that the Gemara took it for granted that even the “nikaf” is in violation of the Torah command, and the question that needs to be answered is why he is liable to punishment, considering his passivity when the violation occurred. By introducing Rabbi Yehuda’s opinion as a possible explanation of the berayta, the Gemara appears to work off the assumption that the “nikaf” is guilty of a violation, regardless of whether he is liable to punishment for this violation. (Indeed, as the Noda Bi-yehuda references, the Ritva proves on this basis that a passive “nikaf” is in violation of the prohibition.)
To answer this question, the Noda Bi-yehuda posits that as a rule, a Torah violation cannot be transgressed without performing any action, unless the Torah makes it clear that it is. For example, by stating that it is forbidden to have chameitz in one’s possession on Pesach, the Torah in effect establishes this prohibition as an exception to the general rule, one which can be violated through inaction – by failing to eliminate one’s chameitz. Similarly, the Torah in several places forbids leaving sacrificial food over beyond its deadline, making it clear that one commits this violation passively, by failing to consume the food in time. With regard to the prohibition of “lo takifu,” the Noda Bi-yehuda writes, the Gemara initially assumed that since the Torah employed the plural form (“takifu,” as opposed to “takif”), and thus addresses both the “makif” and the “nikaf,” this prohibition, too, is transgressed even through inaction. The fact that the Torah directed this command even to the “nikaf,” a passive participant in this process, indicated to the Gemara that this prohibition falls under the exceptional category of prohibitions which can be violated even without performing an action. And so the Gemara at first ascribes the berayta to Rabbi Yehuda, who maintained that when such violations occur, the violator is liable to punishment. The next two opinions cited by the Gemara, however, reflect a fundamentally different understanding. They counter that when the Torah directs itself to the “nikaf,” it speaks specifically to a “nikaf” who plays an active role – either one who removes his own sideburns, or one who actively assists the barber who removes his sideburns. These two views express an entirely new perspective, seeing “lo takifu” as a standard prohibition, which can be violated only through a concrete action, and not through inaction. Hence, as the Kessef Mishneh understood from the Rambam’s formulation, one who passively allows his sideburns to be removed does not violate Torah law at all.