Tosefta su Esodo 21:38

[The Hebrew slave] acquires himself with [loss of] major limbs (see Shemot 21:26). He acquires himself with money via others and a contract via himself, [and he can't acquire with his own money] because he is like one who gives from the left hand to his right [i.e. whatever is his is his master's, so the money needs to come from elsewhere]—words of Rabbi Meir. But Hakhamim say: [Even] money via himself or a contract via others, as long as the money belongs to others and he says to him [when he gives him the money], "[This is] with the understanding that you can only redeem [yourself] with this money". Rabbi Shimon ben Elazar said in the name of Rabbi Meir: Even a contract via others, but not one via himself.

2. Rabbi Yochana ben Zakai used to say five things.

3. There are seven thieveries. First - one who misrepresents [geneivat daat] themselves to others, one who insincerely invites another to their home, one who plies another with gifts they know they will not accept, one who impresses their guest by opening a barrel of wine already sold to a vendor, one who has improper measures, one who lies regarding weights, one who adulterates their merchandise... How do we know misrepresentation is theft? Because it says 'So Absalom stole the hearts of the men of Israel' (II Samuel 15:6)