That we must not take usury
In the thirteenth Psalm: “He that has not given his money upon usury, and has not received gifts concerning the innocent. He who does these things shall not be moved for ever.” Also in Ezekiel: “But the man who will be righteous, shall not oppress a man, and shall return the pledge of the debtor, and shall not commit rapine, and shall give his bread to the hungry, and shall cover the naked, and shall not give his money for usury.” Also in Deuteronomy: “You shall not lend to your brother with usury of money, and with usury of victuals.”
Source: The Treatises of Cyprian (New Advent)