פירוש על ויקרא 25:45

‎ וגם מבני התושבים MORE-OVER FROM AMONGST THE TOLERATED STRANGERS who came from the lands round about you in order to marry Canaanite women in your land and these bear them children; then the child follows the father in respect of nationality, and thus, not being regarded as a Canaanite, is not included in this command, “Thou shalt not keep alive any soul”, but you may purchase him as a servant (cf. Sifra, Behar, Section 6 4; Kiddushin 67b).

Them you may buy. You might ask: Why does Rashi have to explain “Them you may buy”? The answer is: If he did not explain this, I would say that if they had slaves who were sold to them, you may buy those slaves from [among] them, [but the children of the sojourners you may not buy]. Therefore, Rashi explains, “Them you may buy.” I.e., you can buy even them. Another reason Rashi says “Them you may buy” is to say that one may buy the fathers of the sons and even more so the children. But simply understood, I would say that “from them” means one can buy the children of the fathers as slaves, but not the fathers themselves. Therefore Rashi explains, “’From them you may purchase [slaves].’ Them you may buy.” You may buy even the fathers themselves, like the children. [Alternatively], you might ask: Why did Rashi not explain this above in [the previous verse], “From them you may purchase slaves and maidservants?” The answer is: Above, Rashi does not have to explain anything because the verse itself explains, “From them you may purchase slaves and maidservants.” But here where the verse says nothing afterwards and I do not know to what “from them you may purchase” refers., Pperhaps it refers to animals and means as follows, “From them you may purchase animals.” Therefore Rashi has to explain, “Them you may buy.” (Re’m) You might ask: How does Rashi know that “from them” means “them you may buy?” Perhaps “from them” simply means [buying their animals] and not [buying] them? The answer is: Above in parshas Shemos (1:7), it is written, “The land was filled with them (אותם),” and Rashi explains “From them (מהם).” And it is obvious there that the meaning of אותם is ’from them.” Therefore, [Conversely] here too, מהם means “from them.”

מהם תקנו means THEM MAY YE BUY.