Ye shall not round the corners of your heads
The extremities of the hairs of the head, round about, on the forehead, temples, and behind the ears; this is done, as Jarchi says, when any one makes his temples, behind his ears, and his forehead alike, so that the circumference of his head is found to be round all about, as if they had been cut as with a bowl; and so the Arabians cut their hair, as Herodotus F2 reports, (See Gill on Jeremiah 9:26); neither shall thou mar the corners of thy beard;
by shaving them entirely; Jarchi and other Jewish writers say, there are five of them, two on the right, as Gersom reckons them, one on the upper jaw, the other on the nether, and two over against them on the left, and one in the place where the nether jaw joins the right to the left, the chin; the same observes, that it was the manner of idolaters to do the above things; and Maimonides F3 is of opinion that the reason of the prohibition is, because the idolatrous priests used this custom; but this law does not respect priests only, but the people of Israel in general; wherefore rather it was occasioned by the Gentiles in common cutting their hair, in honour of their gods, as the Arabians did, as Herodotus in the above place relates, in imitation of Bacchus, and to the honour of him; and so with others, it was usual for young men to consecrate their hair to idols; but inasmuch as such practices were used on account of the dead, as Aben Ezra observes, it seems probable enough that these things are forbidden to be done on their account, since it follows,
F2 Thalia, sive, l. 3. c. 8.
F3 Moreh Nevochim, par. 3. c. 37. Hilchot Obede Cochabim, c. 12. sect. 1.