Parashas Naso · Passuk 6:07
Even if their father or mother, or their brother or sister should die, they must not become defiled for any of them, since hair set apart for their Godchair set apart for their God Lit. “the restriction of his God.” is upon their head:
Chabad.org — English translation + Rashi
Source: Nazir 48a.
English: “For his father or his mother” — see the parallel in Parashas Emor\ldots and join it here.
In context: The nazir’s stringency exceeds that of an ordinary kohen: even for the closest relatives he may not become impure. The parallel in Emor supplies the comparative framework.
Custom
Chazal compare the nazir’s impurity restrictions with those of the kohen gadol and ordinary kohen.