Deuteronomy 23:19

“Thou shalt not lend upon usury to thy brother . . . Unto a stranger thou mayest lend upon usury--The Israelites lived in a simple state of society, and hence they were encouraged to lend to each other in a friendly way without any hope of gain. But the case was different with foreigners, who, engaged in trade and commerce, borrowed to enlarge their capital, and might reasonably be expected to pay interest on their loans. Besides, the distinction was admirably conducive to keeping the Israelites separate from the rest of the world.”

“Thou shalt not lend upon usury to thy brother - To an Israelite. They held their estates immediately from God, who while he distinguished them from all other people, might have ordered, had he pleased, that they should have all things in common. But instead of that, and in token of their joint interest in the good land he had given them, he only appointed them, as there was occasion, to lend to one another without interest. This among them would be little or no loss to the lender, because their land was so divided, their estates so settled, and there was so little a merchandise among them, that it was seldom or never they had occasion to borrow any great sums, but only for the subsistence of…”

“23:19-20 The word translated interest is related to a noun meaning “bite.” Charging interest was to “put the bite” on the debtor. See also Exod 22:25; Lev 25:36-37; Neh 5:1-13; Ps 15:5.”

“Exo 22:25; Lev 25:35-37; Neh 5:1-7; Psa 15:5; Eze 18:7, Eze 18:8, Eze 18:13, Eze 18:16-18; Eze 22:12; Luk 6:34, Luk 6:35 Deuteronomy 23:20”

“Different Theocratic Rights of Citizenship. - Deu 23:19, Deu 23:20. Of his brother (i.e., his countryman), the Israelite was not to take interest for money, food, or anything else that he lent to him; but only of strangers (non-Israelites: cf. Exo 22:24 and Lev 25:36-37). Deuteronomy 23:21”