Is the practice of not shaving ones beard a custom, or is it proscibed by Jewish law?
Answer The verse: “Ye shall not round the comers of your heads, neither shalt thou mar the comers of thy beard” (Leviticus 19:27) is understood by the talmudic rabbis not to mean that it is wrong for a man to be cleanshaven, but only that facial hair must not be removed with a razor. The standard code of Jewish law, the [16th-century work by Rabbi Yosef Karo,] Shulhan Arukh (Yoreh De’ah, 181:10) rules that it is permitted to remove all facial hair with scissors even when this is done as closely as if with a razor. On the basis of this, many Orthodox Jews shave with an electric razor on the grounds that technically this machine, with its two blades, is not to be treated as a razor. The reason for the prohibition of shaving is not stated in the Bible, but [the 11th-century Spanish/North African sage] Maimonides understands it as a protest against idolatry, conjecturing that the heathen priests shaved their beards. Others have seen it as a means of distinguishing between males and females
