Kiddushin 21B

ההוא לקובעו חובה, ואפילו לרבי יהושע.

The Talmud answers: That verse serves to establish that redeeming him is an obligation. And even according to the opinion of R' Yehoshua, who says that there is no requirement to redeem land, this case is different, as it is proper to redeem him to prevent him from being assimilated by non-Jews.

תא שמע: מה תלמוד לומר ״יגאלנו״ ״יגאלנו״ ״יגאלנו״ שלש פעמים? לרבות כל הגאולות שנגאלות כסדר הזה. מאי לאו בתי ערי חומה ועבד עברי הנמכר לישראל? לא, בתי חצרים ושדה אחוזה. בתי חצרים בהדיא כתיב בהו: ״על שדה הארץ יחשב״! אמר רב נחמן בר יצחק: לקרוב קרוב קודם.

Come and hear a proof from a baraita: What is the meaning when the verse states: “May redeem him,” “may redeem him,” and “may redeem him” (Leviticus 25:48–49), 3 times? This serves to include all redemptions, and that they are redeemed in this order. What, is it not correct to say that this inclusion is referring both to houses of walled cities and a Hebrew slave sold to a Jew, that they can be redeemed by relatives? The Talmud rejects this interpretation: No, it includes houses in open areas and an ancestral field. The Talmud asks: Concerning houses in open areas and an ancestral field, it is written explicitly: “should be reckoned with the field of the country” (Leviticus 25:31). Rav Naḥman bar Yitzḥak said: This teaches that the closer of a relative one is to the seller, the earlier one is in the order of redeeming the house or the field. This is the context of Rav Naḥman bar Yitzḥak’s statement.

והנרצע נקנה ברציעה. דכתיב: ״ורצע אדניו את אזנו במרצע וגו׳״

§ The Talmud returns to the Mishnah, which teaches: And a Hebrew slave who is pierced after serving 6 years is acquired as a slave for a longer period through piercing his ear with an awl. The Talmud explains that this is as it is written: “And his master should pierce his ear with an awl, and he should serve him forever” (Exodus 21:6).