Kiddushin 15B

״ואם לא יגאל באלה״ רבי אומר: באלה הוא נגאל, ואין נגאל בשש.

A Hebrew slave sold to a non-Jew can be redeemed by his relatives, as it is stated: “And if he is not redeemed by any of these, then he should go out in the Jubilee Year” (Leviticus 25:54). R' Yehuda HaNasi says: He can be redeemed only through these, i.e., the assistance of his relatives, and he is not redeemed after 6 years of labor.

שיכול והלא דין הוא, ומה מי שאינו נגאל באלה ⁠– נגאל בשש, זה, שנגאל באלה ⁠– אינו דין שנגאל בשש? תלמוד לומר: ״באלה״⁠ – באלה הוא נגאל, ואין נגאל בשש.

R' Yehuda HaNasi elaborates: As I might have argued that one sold to a non-Jew should be released after 6 years. Could this not be derived through an a fortiori inference: If one who cannot be redeemed by these relatives, i.e., a Hebrew slave who was sold to a Jew, as he cannot be redeemed by his relatives, nevertheless is redeemed after 6 years of labor, is it not logical that this Hebrew slave sold to a non-Jew, who can be redeemed by these relatives, can likewise be redeemed after 6 years of work? Therefore, the verse states “by any of these,” to emphasize that one sold to a non-Jew can be redeemed only through these relatives, and he cannot be redeemed after 6 years.

ואי סלקא דעתך יליף ״שכיר״ ״שכיר״, אמאי קאמר ״ומה מי שאינו נגאל באלה״? נילף ״שכיר״ ״שכיר״!

The Talmud explains the proof: And if it enters your mind that R' Yehuda HaNasi derives the verbal analogy between “hired worker” and “hired worker,” why does he say: If one who cannot be redeemed by these, with regard to one who is sold to a Jew? Let him derive that halakha from the case of one sold to a non-Jew, through the verbal analogy between “hired worker” and “hired worker.” The term “hired worker” is used in reference to one sold to a non-Jew as well: “As a hired worker year by year he should be with him” (Leviticus 25:53), and accordingly one can say that even one sold to a Jew can be redeemed by his relatives. The fact that he does not accept this claim indicates that R' Yehuda HaNasi rejects the verbal analogy between “hired worker” and “hired worker.”