Hashem’s Holy Name
‘A Gentile May Bring Either Votive Or Freewill Offerings…’
(Menachos 73b)
Rabbi Akiva on our daf derives from “ish ish mibeis Yisrael u’min ha’ger b’Yisrael asher yakriv korbano l’chol nidreihem u’l’chol nidveihem – a man, any man of the house of Israel and of the proselytes among Israel who will bring his offering for any of their vows or their free-will offerings” (Vayikra 22:18) that not only may a Jew pledge an offering; a gentile may do so, too.
Not Bound
Tosafos (Nazir 16b sv “hanicha l’man d’amar”) indicates that a gentile is not halachically bound to keep his promise to offer a sacrifice since “lo yachel de’varo – he shall not desecrate his word” (Bamidbar 30:3) is not one of the seven Noahide laws.
Acceptability For The Altar
R. Elazar (Avodah Zarah 5b) derives from “U’mi’kol ha’chai mi’kol basar shenayim mi’kol tavi el ha’teivah – And from all that lives, of all flesh, two of each shall you bring into the Ark” (Bereishis 6:19) that the animals sacrificed from among these were to be whole, not missing limbs.
Tosafos (Avodah Zarah 5b, 2nd sv “minayin l’mechusar ever…”) notes that we cannot say that a gentile who promises to offer a sacrifice and then offers one with a missing a limb has sinned since the seven Noahide laws does not include anything about offering whole sacrifices. But he still must offer another sacrifice to fulfill his pledge.
Oaths Before Mattan Torah
The Mishnah LaMelech (on Hilchos Melachim 10:7) asks: If a gentile is not halachically-bound to keep his vow, what was the significance of the oath taken by Avimelech when he made a treaty with Avraham (Bereishis 21:23)? Also, why did Avraham compel Eliezer to take an oath that he would not take a Canaanite wife for Yitzchak (Bereishis 24:3)?
Birkat Hashem
The Mishnah LaMelech suggests that although a gentile is not duty-bound to keep his vow, he cannot violate it either since doing so would amount to birkat Hashem (cursing Hashem), which is one of the seven Noahide laws.