Nehemiah 5:8

5:8 I said to them, “To the extent possible we have bought back our fellow Jews who had been sold to the Gentiles. But now you yourselves want to sell your own countrymen, so that we can then buy them back!” They were utterly silent, and could find nothing to say.

Nehemiah 10:31

10:31 We will not buy on the Sabbath or on a holy day from the neighboring peoples who bring their wares and all kinds of grain to sell on the Sabbath day. We will let the fields lie fallow every seventh year, and we will cancel every loan.