Musar su Levitico 19:27

And likewise with destruction of the beard, as it is stated (Leviticus 19:27), “and you shall not destroy the side-growth of your beard.”

ולא תשחית את פאת זקנך...לא תקיפו פאת ראשכם . The reason for this string of prohibitions concerning the defacing of the head or the skin is to make a clear distinction between our mode of living and that of the pagan priests. A G–d-fearing person does not use the razor anywhere near his throat so that he may not accidentally injure his skin close to where his sideburns grow. The use of scissors in all those areas is permitted. Since we have the principle that the commission of one sin usually triggers the commission of other sins, the Torah prohibits using the razor on "the corner of your head,” so that, having failed to observe this injunction you should not also become guilty of using it on the "corners of your beard."