The 209th prohibition is that a Nazirite is forbidden to cut his hair.
The source of this commandment is G‑d's statement,1 "No cutting instrument shall come upon his head."
The one who cuts the Nazirite's hair also receives lashes, since the one who cuts and the one whose hair is cut are both treated the same.2 The punishment of lashes applies as soon as one hair is cut.3
All the details of this mitzvah are explained in the tractate devoted to this subject [tractate Nazir].
