The book of Leviticus in the Bible appears to completely forbid the shaving of the corners of the head and prohibits the marring of the corners of the beard, with particular emphasis on priests not marring the corners of the beard; as with many other parts of the Leviticus, the Book of Ezekiel describes similar regulations, stating that the priests should not shave their heads, or let their locks grow long.
However, there were clearly exceptions, with the Book of Ezekiel itself adding that priests should keep their hair trimmed, and Leviticus arguing that, in certain cases of tzaraath, the beard and hair should be completely shaved away. Leviticus additionally requires that Nazarites shave their heads, 7 days after any contact with corpses, and the Deuteronomic Code compels captive women to shave their head after the conclusion of mourning for their parents
According to biblical scholars, the shaving of hair, particularly of the corners of the beard, was originally a mourning custom; the behaviour appears, from the Book of Jeremiah, to also have been practiced by Arabic tribes, although some ancient manuscripts of the text read live in remote places rather than clip the corners of their hair. Biblical scholars think that the regulations against shaving hair may be an attack on the practice of offering hair to the dead, which was performed in the belief that it would obtain protection in sheol; Nazarites shaved after contact with a corpse, captive women shaved after mourning the death of their parents, and the general prohibition in the Holiness Code is immediately followed by a rule against people cutting their own bodies for the benefit of the dead.
Textual scholars date the Priestly Source, and the Holiness and Priestly Codes within it, to the late 7th century or later; it appears that before this time, the shaving of the head during mourning was permitted, and even encouraged. The Book of Amos, which is dated by textual scholars to the mid 7th century, as well as the Books of Isaiah and of Micah, which textual scholars date to a slightly later period, portray HaShem as instructing the Israelites to shave their head as an act of mourning:
The prohibition against cutting the corners of the beard may also have been an attempt to distinguish the appearance of Israelites from that of the surrounding nations, and reduce the influence of foreign religions; Maimonides criticises it as being the custom of idolatrous priests. The Hittites and Elamites were clean-shaven, and the Sumerians were also frequently without a beard; conversely, the Egyptians and Libyans shaved the beard into very stylised elongated goatees. In the Book of Genesis, Joseph is described as having shaved his beard, and scholars think it likely that the Egyptian style is the form to which the passage refers.
The forbidding of shaving the corners of the head was interpreted by the Mishnah as prohibiting the hair at the temples being cut so that the hairline was a straight line from behind the ears to the forehead; thus it was deemed necessary to retain sidelocks, leading to the development of a distinctly Jewish form of sidelock, known as payot. As for the Beard, more complicated views arose; the corners of the beard were interpreted to refer to five extremities, namely the point on each cheek near the temples, the point at the end of the cheek bone towards the centre of the face, and the point of the chin.
Because the biblical prohibition against shaving uses the Hebrew word gelech (גלח), which refers to shaving with a blade against the skin, Talmudic rabbis interpreted it to only refer to single-bladed razors, and only to situations that involve the hair being cut close to the roots, in a smooth manner. Nevertheless, the Mishnah also records conservative opposition to this view, represented by the opinion of Eliezer ben Hyrcanus, who forbade any removal of the beard by any mechanism, arguing that the beard was given to men in order to distinguish them from women . In classical Palestine, it was common among more scholarly circles of Jews to clip beards, but the Jewish masses didn't believe that there should be a distinction between clipping a beard and shaving it
Ezekiel's request for priests to keep their hair trimmed was read by the Talmudists as referring specifically to the artistic Lydian style of haircut, in which the ends of the hair of one row reaches the roots of the next. This hairstyle was apparently a distinguishing feature of the nobility, as the common population shaved their heads entirely except for the sidelocks; the king is said to have had his hair cut in this manner each day, the Jewish High Priest to have done so each week just before the Sabbath, and ordinary Jewish priests to have done so every thirty days. The Talmudic Rabbis also argue that anyone who was constantly in contact with government officers could adopt tonsures, although they do state that to everyone else it was forbidden; during the period of Hellenic domination over Judah, the tonsure was a fashionable haircut among the Greeks.
Gradually, various mechanisms developed by which Jews evaded the shaving regulations of Jewish law. The Shulchan Aruch argued that because scissors have two blades, it would therefore be permitted to trim the beard by using them, since the cutting action would come from contact between two blades and not from that between blade and skin. In Germany and Italy, by the end of the seventeenth century, Jews started removing beards with the aid of pumice stones and chemical depilatories, which would leave the face smooth, as if it had been shaven; at the time, this was strenuously opposed, somewhat hopelessly, by Hillel ben Naphtali Zevi and Joseph Fiametta. Menachem Mendel Schneersohn (Tzemach Tzedek) argued that shaving a beard would fall under the biblical regulation against males resembling a female (he also extended the prohibition for wanton destruction to destroying the hair of the beard); the Shulchan Aruch interpreted this regulation in a different way, arguing that it forbade men from removing hair from areas where women were accustomed to remove hair, such as underarm hair.
In the early Middle Ages, Jewish custom, in regard to beards, followed the fashions of each nation; in Germany, France, and Italy, Jews removed their beards, but in Islamic nations, Jews grew them long. In 1720, a violent confrontation arose between a group of Italian Jews, who had migrated to Salonica in Turkey, and the local Jewish population, because the migrant Italians didn't wear beards, but the local population insisted that beards should be worn. Among the western Europeans, the Ashkenazi rabbis attempted to oppose the beard cutting behaviour of the Jewish populace, and empatically forbade the cutting of the beard, but the Sephardim interpretated the Talmudic and Biblical shaving regulations in particularly lax ways. It was later remarked by Jacob Emden that the Jewish population in western Europe had objected to these regulations so much that it had been impractical to enforce them; there had also been prominent opponents of beards, such as Joseph Solomon Delmedigo, to whom is attributed the epigram:
The Zohar, one of the primary sources of Kabbalah (a form of Jewish mysticism), attributes holiness to the beard, and strongly discourages its removal, declaring that even the shortening of a beard by scissors was a great sin; it was even said that Isaac Luria, a significant figure in the history of Kabbalistic mysticism, meticulously avoided touching his beard, lest he should accidentally cause hairs to drop from it. Kabbalistic teachings gradually spread into Slavonic regions, and consequently beard trimming was prohibited in these areas, even if it involved scissors; it was the Hasidic Jews who more closely followed Kabbalistic practices than Jews of a Lithuanian or misnagdim background, and thus it became the Hasidic Jews who are known for the distinctive traditional practice of growing their beards. However, in Italy, shaving the beard was so popular that even the Italian followers of Kabbalah did it; an Italian Kabbalist even went to the extent of arguing that beard shaving was only prohibited in Canaan, and was actually to be encouraged elsewhere
Some Orthodox Jews, including Hassidim, refrain from cutting their beards altogether, and with the exception of occasionally trimming their moustaches when they interfere with eating, never cut their facial hair. Those Orthodox Jews who do shave their facial hair must utilize electric shavers. Some rabbis have deemed certain electric shavers permissible, because even though they "destroy" the beard, they do this through a permitted scissor-like action. Other rabbis do not permit any electric shavers, presuming that scissors which cut as closely as a razor would are prohibited as well.
The advent of "Lift and Cut technology" by Philips (initially marketed under the Philishave and Norelco brand names) in 1980, with which shavers are said to first lift the hair with a primary blade and then slice it with a secondary blade, raises the question of whether or not this constitutes use of a single blade. According to the company, the secondary blade no longer works in concert with the comb of the rotary head to produce a scissor action. Many Orthodox rabbis have banned Lift and Cut shavers for this reason. But some permit them on the basis of their research conclusions that, despite company claims, the second blade does not in fact cut on its own, but rather requires the presence of the comb to create a scissors-like cutting action. In any case, a person who wishes to follow the stricter opinion can remove the Lift and Cut primary blades from the rotary blade head assembly.
Some modern Jewish religious legislators in Orthodox Judaism, including Moshe Feinstein and Yosef Eliyahu Henkin, permit the use of electric razors for the purpose of remaining clean shaven, because, in their view, electric razors work like scissors, cutting by trapping hair between the blades and a metal grating. However, other modern Jewish Rabbinical authorities, such as Avraham Yeshayahu Karelitz and Yaakov Yisrael Kanievsky, consider electric razors, particularly rotary models which use "Lift and Cut" heads made by Philips, to work in the manner of primitive razors, and consequently prohibit their use These shavers can be used if the lifters attached to the shaver's cutters are removed first. The rotary electric shaver was invented by a Jewish engineer named Alexandre Horowitz. Many Orthodox Jews prefer to grow beards, for a variety of religious, social, and cultural reasons, even if they believe that electric shavers would be permitted; many Orthodox Jews, even non-Haredi Jews, today grow beards to keep the tradition of their ancestors, regardless of the permissibility of their removal.