As we noted on yesterday’s daf, the mitzva of yibum is an example of the classic rule aseh dokheh lo ta’aseh – that performance of a positive commandment can push aside a negative commandment. Our Gemara continues its discussion of other such cases and their sources.
Someone suffering from tzara’at is obligated to remove himself from the community until he recovers. Once his lesions are declared to be non-leprous, he undergoes a ritual purification ceremony as preparation for his return to the community, which involves shaving off all of the hair on his body (see Vayikra 14:1-9). This commandment stands in apparent contradiction to the prohibition forbidding shaving one’s peyot (see Vayikra 19:27), yet is expressly permitted by the Torah – another case of aseh dokheh lo ta’aseh.
The prohibition against cutting off peyot is understood by the Mishna in Kiddushin to apply only to men and not to women, since the Torah places this negative commandment in the same context as the prohibition against “destroying” one’s beard (which is understood as forbidding shaving with a razor), something that does not apply to women. According to the Torah, one is not obligated to leave the area of the peyot untouched, but rather a person is not allowed to have his hair cut in such a way that the hair of his temples would be even with the hair behind his ears.
The Rambam suggests that these prohibitions stem from a connection with avodah zara – idol worship – and that these types of haircuts were part of idolatrous practice, as the priests would cut their hair in this fashion (see the Rambam in Hilkhot Avodat Kokhavim 12 :1,7). Others simply say that this law is a gezeirat ha-katuv – a rule in the Torah whose explanation we cannot fully understand.