Neither shall they shave their heads, nor suffer their locks to grow long; they shall only poll their heads.
Neither shall they shave their heads - as mourners used to do, and as the Levitical priests were forbidden to do (Leviticus 21:1-5). The worshippers of the Egyptian idols Serapis and Isis shaved their heads; another reason why Yahweh's priests are not to do so.
Nor suffer their locks to grow long - as the luxurious, barbarians, and soldiers in warfare did (Jerome).