Reference for Menachot 146:18

דתנו רבנן (ויקרא ה, יג) והיתה לכהן כמנחה שתהא עבודתה כשרה בו

Speak unto the children of Israel and say unto them, When either man or woman shall clearly utter a vow, the vow of a Nazirite, to consecrate himself unto the Lord:<span class="x" onmousemove="('comment',' Mum. VI, 2.');">¹⁶</span> hence only the children of Israel can vow the vow of a Nazirite, but gentiles cannot vow the vow of a Nazirite!-From the former teaching I should only have said that they may not offer the Nazirite-offerings, but that the Nazirite vow does apply to them; [the latter passage] therefore teaches us [that it is not so].

Jastrow