251. Payes: The prohibition against rounding the sides of the head
Do not round the corners of your head… (Leviticus 19:27)
Jewish men are prohibited to shave off or otherwise remove the hair on their temples in front of the ears (basically, the upper part of one’s sideburns). The “corners” of one’s head are called payos (or payes), which is what people colloquially call the hair that grows there, which some Jews wear long as sidelocks.
The reason for this mitzvah is that God wants us to remain distinct from other nations as a means to distance us from sin. Having a distinct style serves as a reminder of who we are and that we have special obligations that may not be overlooked.
It is prohibited for a man to cut the area of his payes or to have it done; it is also prohibited to cut off someone else’s payes (something to keep in mind if you’re considering a career as a barber!). One may likewise not cut off a young boy’s payes. A man would be separately liable for cutting the hair off of each side. Women are exempt from this law because it is connected to the rule against destroying the beard in the next mitzvah. Since they are exempt, they bear no liability for shaving themselves or others.
This mitzvah applies to men only, at all times and in all places. It is discussed in the Talmud in the tractates of Makkos (20a-21a), Nazir (57b) and Kiddushin (35b). This mitzvah is codified in the Shulchan Aruch in Yoreh Deah 181. It is #43 of the 365 negative mitzvos in the Rambam’s Sefer HaMitzvos and #176 of the 194 negative mitzvos that can be fulfilled today as listed in the Sefer HaMitzvos HaKatzar of the Chofetz Chaim.