- Bal takif (not to shaving their payot – the “corners” of the hair on one’s head – see Vayikra 19:27)
- Bal tash’hit (not to shave one’s beard – according to the Gemara, with a razor – see Vayikra 19:27)
- Bal titmah le-metim (a kohen cannot come into contact with a dead body – see Vayikra 21:1).
In searching for sources for these laws the Gemara points out that the commandment that kohanim refrain from ritual defilement is clearly directed to men only – “bnei Aharon, ve-lo bnot Aharon” (see Vayikra 21:1). The suggested source that excludes women from cutting their payot and beards is the juxtaposition of the hair of one’s payot with the hair of one’s beard in the passage in Vayikra (19:27): “Lo takifu pe’at roshkhem ve-lo tsh’hit et pe’at zekanekhah.” The Gemara argues that the law that applies to the beard also applies to the payot, and since women do not ordinarily have a beard, the prohibition against shaving one’s beard does not apply to them, thus the prohibition against cutting payot does not apply to them either.
With regard to men, our Gemara concludes that since the Torah used the term lo tash’hit (“do not destroy”) with regard to cutting one’s beard, the prohibition regarding shaving one’s beard would only be with a razor, which is mash’hit (“destructive”), but mispara’im ke-en ta’ar – a scissor-like cutting action that removes hair – is permitted. Based on this, most rishonim permit shaving one’s beard if it is done using that method, but they still prohibit cutting one’s payot against the skin even mispara’im ke-en ta’ar, since regarding this halakha the Torah forbids the very act of hakafa (rounding the “corners”.) The Rambam, however, disagrees, apparently because he takes the juxtaposition of bal takif and bal tash’hit very seriously, concluding that all of the laws of one apply to the other, as well. Thus, just as one’s beard can be cut with a scissors, so one’s payot can be cut with a scissors.
(It is interesting to note that in the famous portrait of the Rambam he does not appear to have payot.)
It should be noted that based on kabbalistic sources, the HaAri forbade cutting one’s beard under all circumstances.