מדרש אויף שמות 21:2

(Exodus 21:2) "If you buy a Hebrew man-servant": Scripture here speaks of one sold by beth-din (to pay for what he has stolen), in which instance he serves both the father and the son. But perhaps it speaks of one who sells himself (because of poverty)? (This is not so, for (Leviticus 25:39) "And if your brother grows poor with you, and he is sold to you" speaks of one who sells himself. How, then, am I to understand "If you buy a Hebrew man-servant"? As referring to one who is sold by beth-din because of his theft, that he serves the master and his son.

1) (Vayikra 25:39) ("And if your brother grows poor with you, and he is sold to you, do not work with him the work of a servant.") Whence is it derived that one is not permitted to sell himself and place (the proceeds) in his money-bag to buy animals, vessels, or a house unless he became impoverished? From "And if your brother grows poor and he is sold" — He may not sell himself unless he becomes poor. And whence is it derived that when he is sold, he shall be sold only to you (and not to a gentile)? From "and he is sold to you." And whence is it derived that if beth-din sell him they sell him only to you? From (Devarim 15:12) "If there be sold to you." "your brother": You shall treat him as a brother. I might think that he should conduct himself as a brother; it is, therefore, written "a servant." I might think that you shall also conduct yourself to him as a servant; it is, therefore, written "your brother." How so? You conduct yourself to him with brotherhood (i.e., you call him "brother"); he conducts himself to you with servitude (he calls you "master").

Variantly: What is the intent of "and he shall go out alone"? Because it is written (of a Hebrew man-servant) "six years shall he serve," I might think that it is only with such a servant that the above provision obtains (i.e., that his master may give him a Canaanite maid-servant). Whence do I derive the same for one whose ear has been bored? (see below) From "and he shall go out alone" — to include one whose ear has been bored.