Sefer HaChinuch ספר החינוך

To lend to the gentile with interest: That we were commanded to request interest from the [other] peoples when we lend to them and that we not lend to them without interest. And about this is it stated (Deuteronomy 23:21), “Take interest from the foreigner.” And likewise is it permitted to borrow from them with interest. And they said in Sifrei, “‘Take interest from the foreigner’ — that is a positive commandment; ‘and from your brother, do not take interest’ — that is a negative commandment.”

It is from the roots of the commandment that it is fitting for us to do acts of loving-kindness only to the nation that knows God and serves in front of Him. And by refraining from kindness with other people and doing it with these, it becomes clear that the main love and pity on them is [coming] from the angle of their following the Torah of God, may He be blessed. And behold, with this intention, there will be reward for us in our refraining from kindness to them, [just] like [there will be] in our doing it to the children of our nation.

From the laws of the commandment is that which they, may their memory be blessed, said (Bava Metzia 71a) that it is a commandment to prioritize a free loan to an Israelite over lending to a gentile with interest; and that which they said (Bava Metzia 72a and see Mishneh Torah, Creditor and Debtor 5:1) that [if] a gentile borrowed money from an Israelite with interest — even though he converted — [the Israelite] should collect from him all the interest that accrued until he converted; so that they will not say, “He converted to not pay the interest.” And in the same manner that we were commanded to request interest from them, so too is it permissible to give them interest; since the verse only prohibited [taking] interest of an Israelite — the matter is known. And they, may their memory be blessed, said (Bava Metzia 71b and see Mishneh Torah, Creditor and Debtor 5:4) that [if] a gentile borrowed money from an Israelite and wanted to pay back [the loan] and found another Israelite and [that Israelite] said, “Give it to me and I will give you the interest from it, in the [same] way that you give it to the Israelite,” it is permissible. But if [the gentile] stood [this Israelite] in front of the Israelite [lender] — even though the gentile gives the money to the hand of [the Israelite borrower] — since [the gentile] gave the money with the knowledge of the Israelite [lender], behold it is fixed interest (and forbidden). And they, may their memory be blessed, said (Bava Metzia 70b and see Mishneh Torah, Creditor and Debtor 5:2) that even though their interest is permissible according to the [letter of the] law, it is [still] forbidden for an Israelite to lend to them with fixed interest, more than what he needs for his livelihood; so that he not become accustomed to always be with him and learn from his deeds. But it is permissible to take “the dust of interest (avak ribit),” even if it is more than what he needs for his livelihood — since he will not be so accustomed to be with him for the sake of the “dust of interest.” And a Torah scholar may lend whatever he wants, as there is no concern about him that he will learn from [the gentile’s] deeds; since “wisdom emboldens the sage and guards him forever.” And the rest of its details are elucidated in the chapter [entitled] Eizehu Neshekh in Bava Metzia. (See Tur, Yoreh Deah 159, 160.)

And [it] is practiced in every place and at all times by males and females. And one who transgresses it and lends without interest from the perspective of kindness alone — not from the hope about him that he will profit from him from another angle, or because of the ways of peace — has violated this positive commandment. And Ramban, may his memory be blessed (in his critiques of the Sixth Root and at the end of his critiques of the Sefer HaMitzvot) does not count this positive commandment in the calculation of the [613] commandments. And he says that this verse only came to give a positive [as well as] a negative commandment for one who lends to an Israelite with interest. And this is the intention of the midrash in Sifrei, in its saying that this is a positive commandment. And so does it appear from the words of the Gemara at the end of the chapter [entitled] Eizehu Neshekh. But with all of this, “we walk in the way of the king” — “we will not veer to the right or left” from [Rambam’s] calculation. And great is the one whose mistakes are numbered (few in number).