This is the law for the Nazirite who takes a vow: This sentence refers back to the entire preceding section. Revised English Bible brings this out clearly by saying “Such is the law for the Nazirite who has made his vow,” and so does New Jerusalem Bible with “Such is the ritual for the nazirite.” Some languages may have to be more explicit by saying “All these instructions apply to the ritual concerning Nazirites.” Law renders the Hebrew word torah, as in verse 13 (see the comments there).

His offering to the LORD shall be according to his vow as a Nazirite: For offering, which renders the Hebrew word qorban, see the comments on verse 14.

Apart from what else he can afford is literally “from besides what his hand will reach.” The regulations in this section only give the minimal requirements for a Nazirite. Nazirites are encouraged to offer more if they can. New Living Translation expresses this clause clearly by saying “They may also bring additional offerings if they can afford it.”

In accordance with the vow which he takes, so shall he do according to the law for his separation as a Nazirite: The repetition here emphasizes that Nazirites must fulfil the regulations governing them, including giving what they promise.

The following model for this verse is based on New Revised Standard Version and Bible en français courant:
• “Such is the ritual concerning those who are consecrated to the LORD by a vow; and such are the gifts they should offer to the LORD on that occasion. If they can add other gifts, they may do so; but in any case, what they promise they must offer, strictly following the ritual for their consecration.”

The adverb “strictly” conveys the emphasis expressed by the repetition in the Hebrew here.

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 .