Leviticus 25:23-36: The land shall not be sold for ever: for the land is mine; for ye are strangers and sojourners with me. And in all the land of your possession ye shall grant a redemption for the land. If thy brother be waxen poor, and hath sold away some of his possession, and if any of his kin come to redeem it, then shall he redeem that which his brother sold. And if the man have none to redeem it, and himself be able to redeem it; Then let him count the years of the sale thereof, and restore the overplus unto the man to whom he sold it; that he may return unto his possession. But if he be not able to restore it to him, then that which is sold shall remain in the hand of him that hath bought it until the year of jubile: and in the jubile it shall go out, and he shall return unto his possession. And if a man sell a dwelling house in a walled city, then he may redeem it within a whole year after it is sold; within a full year may he redeem it. And if it be not redeemed within the space of a full year, then the house that is in the walled city shall be established for ever to him that bought it throughout his generations: it shall not go out in the jubile. But the houses of the villages which have no wall round about them shall be counted as the fields of the country: they may be redeemed, and they shall go out in the jubile. Notwithstanding the cities of the Levites, and the houses of the cities of their possession, may the Levites redeem at any time. And if a man purchase of the Levites, then the house that was sold, and the city of his possession, shall go out in the year of jubile: for the houses of the cities of the Levites are their possession among the children of Israel. But the field of the suburbs of their cities may not be sold; for it is their perpetual possession. And if thy brother be waxen poor, and fallen in decay with thee; then thou shalt relieve him: yea, though he be a stranger, or a sojourner; that he may live with thee. Take thou no usury of him, or increase: but fear thy God; that thy brother may live with thee.

Usury is what we call today "interest". Under the law of Moses it was forbidden to charge interest on loans; this would have been a lack of charity.