Exodus 21:2

כי תקנה עבד עברי IF THOU BUYEST AN עבד עברי — This means a servant who is a Hebrew. Or perhaps this is not so, but it means a servant of a Hebrew (one who had been the servant of a Hebrew), i. e. a Canaanitish servant whom thou hast bought from an Israelite, and it is with regard to him that Scripture states “six years he shall serve”! — And if you ask, how I will then explain the commandment, (Leviticus 25:46) “and you shall leave them (the Canaanitish servants) as an inheritance for your children [and they shall serve you forever]”? then I reply, that this refers to the case of a Canaanitish servant who has been bought from a heathen; but if such a servant has been bought from an Israelite he shall go free at the end of six years! — This explanation that our text refers to a Canaanite servant will not hold, for Scripture states, (Deuteronomy 15:12) “and if thy brother an Hebrew man be sold unto thee [and serve thee six years, then in the seventh year thou shalt let him go free from thee]” — the Torah says, as it were, by using the two terms העברי and אחיך: I tell you this (that the servant shall go free in the seventh year) only with regard to thy brother! Consequently Leviticus 25:46 has to be applied to any Canaanite servant, whether bought from a Hebrew or from a heathen and עבד עברי in our text can only denote עבד שהוא עברי. (Mekhilta) ‎כי תקנה IF THOU BUYEST [AN HEBREW SERVANT] — This means an Hebrew servant whom thou hast bought from the hand of the court which sold him for a theft which he had committed, as it is said, (Exodus 22:2) “if he (the thief) have nothing, then shall he be sold for his theft”. Or perhaps this is not so, but Scripture is referring to the case of one who sells himself as a servant on account of his destitution, whilst he who has been sold by the court for his theft shall not go free at the end of six years! This assumption it erroneous, for when Scripture states, (Leviticus 25:39, 40) “and if thy brother that dwelleth by thee be waxen poor, and he sells himself unto thee … [he shall serve thee unto the year of jubilee]”, it is plain that in this passage there is mentioned the case of one who sells himself on account of his destitution. How then must I explain כי תקנה in this verse? Obviously as referring to him who was sold by the court (Mekhilta). לחפשי means INTO FREEDOM (i. e. חפשי is a noun like חֹפֶשׁ but having a redundant י at the end).

כִּ֤י תִקְנֶה֙ עֶ֣בֶד עִבְרִ֔י שֵׁ֥שׁ שָׁנִ֖ים יַעֲבֹ֑ד וּבַ֨שְּׁבִעִ֔ת יֵצֵ֥א לַֽחׇפְשִׁ֖י חִנָּֽם׃

If thou buy a Hebrew servant, six years he shall serve: and in the seventh he shall go out free, for nothing.