All the days that he separates himself to the LORD: This phrase is similar to the initial phrases of verses 4 and 5 (see the comments there).
He shall not go near a dead body: Nazirites must not go near corpses. The Hebrew verb rendered go near is simply “come.” It does not necessarily imply “touch.” Contemporary English Version expresses it well here with “go close to.” Body renders the Hebrew word nefesh. As mentioned at 5.2 (see the comments there), the word nefesh can refer to humans and animals. But in this context it primarily refers to dead humans. New Jewish Publication Society’s Tanakh renders a dead body as “a dead person.”
Neither for his father nor for his mother, nor for brother or sister, if they die, shall he make himself unclean: This clause in Hebrew emphasizes that Nazirites should not even go near the corpses of close family members. If they do, they will become ritually impure. For the Hebrew verb rendered make himself unclean, see 5.3, where it is translated “defile.” Revised Standard Version‘s literal rendering of this sentence is awkward in English. Good News Translation expresses more clearly the emphasis on the personal restriction here by saying “you must not defile yourselves by going near a corpse, not even that of your father, mother, brother, or sister.”
Because his separation to God is upon his head: Nazirites must not go near corpses because their uncut hair shows they are dedicated to serve God. Good News Translation makes it clear that this clause is actually about the Nazirites’ hair by saying “Your hair is the sign of your dedication to God.” Good News Translation has also rearranged the order of clauses in verses 6-7 by beginning with this reason clause, which other languages may find helpful. For the Hebrew word rendered separation, which comes from the same root as the word for “Nazirite,” see verse 4.
Quoted with permission from de Regt, Lénart J. and Wendland, Ernst R. A Handbook on Numbers. (UBS Helps for Translators). Miami: UBS, 2016. For this and other handbooks for translators see here .