Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 205
The full Hebrew text of Mishneh Torah, Negative Mitzvot, Chapter 205, with English translation by Maimonides (Rambam).
שלא יאכל חרצנים, שנאמר "מחרצנים . . . לא יאכל" (במדבר ו,ד).
[For a Nazarite] not to eat grape seeds, as [Numbers 6:4] states: "He shall not eat [anything from wine grapes] from its seeds...."