Leviticus 25:49

Either his uncle, or his uncle’s son, may redeem him. — That is, any of his relatives are to redeem him, which is not the case when an Israelite sells himself to one of his own nation. Hence the Jewish canons enacted that “if a Hebrew is sold to a stranger, and is unable to redeem himself, his kinsmen must redeem, nay, the Sanhedrin are to compel his kinsmen to redeem him lest he should be lost among the heathen. If his kindred do not redeem him, and if he cannot redeem himself, every man of Israel is commanded to redeem him. But if he is sold to an Israelite his kindred may not redeem him, nor may he borrow money to redeem himself, nor redeem himself by instalments.” In accordance with this injunction we find the Jews declare “we after our ability have redeemed our brethren the Jews which were sold unto the heathen, and will ye even sell your brethren, or shall they be sold unto us?” (Nehemiah 5:8).