Nazir 62B

מתני׳ חומר בעבדים מבנשים, שהוא מפר נדרי אשתו, ואינו מפר נדרי עבדו. הפר לאשתו ⁠— הפר עולמית. הפר לעבדו ⁠— יצא לחירות ומשלים נזירותו.

Mishnah: The previous Mishnah taught that the naziriteship of women includes a stringency that does not apply to slaves. This Mishnah adds: There is a greater stringency in the case of slaves than in the case of women, as a man can nullify the vows of his wife but he cannot nullify the vows of his slave, despite the fact that he can prevent him from fulfilling them in practice. Similarly, if he nullified the naziriteship of his wife it is permanently nullified, and it remains nullified even if she is later divorced or widowed. Conversely, if he nullified the naziriteship of his slave by forcing him to violate the terms of his vow of naziriteship, when the slave is emancipated he completes his naziriteship.

גמ׳ תנו רבנן: למה רבו כופו? לנזירות, אבל לא לנדרים ולערכין.

Talmud: A baraita states (Tosefta 6:4): With regard to what matter can his master force a slave? With regard to naziriteship. However, he cannot force his slave in the case of other vows and valuations. This baraita is apparently saying that a master cannot prevent his slave from fulfilling the terms of a vow.

מאי שנא גבי נזיר ⁠— דאמר רחמנא ״לאסר אסר על נפשו״, במי שנפשו קנויה לו ⁠— יצא עבד שאין נפשו קנויה לו. אי הכי, אפילו גבי נדרים נמי!

The Talmud asks: What is different with regard to a nazirite that a master can force his slave to transgress his naziriteship, as God states: “To bind his soul with a bond” (Numbers 30:3), from which it is inferred that the Torah is referring only to one whose soul is in his possession, i.e., who is not owned by another; this excludes a slave, whose soul is not in his possession because he is under his master’s control. If so, then even with regard to vows that same halakha should apply as well, as that verse is written in the context of vows in general, not specifically vows of naziriteship. Why is a master unable to compel his slave to break a vow?