Did you ever wonder why many Jews or Orthodox Jews have beard and some of them have curls or sidewalks?
Well, the answer is partially based on law and partially based on custom. The part that is based on law is based on a verse in Leviticus chapter 19 verse 27. The verse reads you shall not round off to the corner of your head and you shall not destroy the edge of your beard.
The rabbi’s interpret this event to be meaning, that a person should not shave their beard off with a razor, which is why it is forbidden for Jews to shave with a razor, and that’s why many Jews use trimmers or machine that don’t involve this prohibition of shaving with a razor.
Other Jews however, just took upon themselves the custom of growing a beard to avoid the issue altogether, and since shaving with a razor is the smoothest shave, and the easiest many just decides to grow beard and avoid the whole issue altogether.
It also helps them avoid a controversy of which kind of shavers are permitted and which are not and how would you do it so, that’s why many Jews do have beards.
That also explains why some Jews have curls on the side because, the verse says that a person should not round off the corner of their head, which means you can’t completely shave the side of your head.
So, it’s good enough if you just leave a bit of hair, but some people in order to sort of keep the face zone and a buffer zone has developed a custom of growing curls, so that they don’t even get close to that area and don’t shave anything that they should not be shaving.