At first, usury indicated the charging of any kind of interest, and in some Christian cultures and even today in many Islamic societies, imposing any interest charges at all is deemed as usury. Throughout history, various domains from ancient Greece to medieval Europe have condemned loans with any interest. However, the Roman Empire ultimately allowed loans with restricted interest rates, and the Catholic Church in medieval Europe forbade the charging of interest at any rate. Religious prohibitions on usury have been asserted within the tenet that charging interest on a loan is a sin.
The definition of usury is the illegal action or practice of lending money at unreasonably high rates of interest. This means requiring those who receive a loan of money to pay back a substantially higher amount in return. Criticisms of usury include that it is predatory in nature taking advantage of people desperate for money.
According to Dictionary.com, “usury” has the following definitions:
The word usury has arrived in modern English to mean unreasonable interest upon money loaned, either formally illegal or at least oppressive. In the Scriptures, however, the word did not have this purpose but indicated simply interest of any kind upon money. The Jews were prohibited by the law of Moses to take interest from their brethren but were allowed to take it from foreigners. The prohibition grew out of the agricultural status of the people, in which ordinary business loans were not needed and loans, as were required, should be made only as to friends and brothers in need. Usury is also defined as the practice of mortgaging land, sometimes at exorbitant interest, which grew up among the Jews during the captivity, in direct violation of the law. (Leviticus 25:36-37; Ezekiel 18:8-17)
In the Old Testament, the Israelites were forbidden from charging “usury,” or interest, on loans to fellow Jews (Deuteronomy 23:19), but they were permitted to charge interest on loans to foreigners (Deuteronomy 23:20). A mention of this usury law in Leviticus 25:35-38 makes it apparent that it applied to loans made to fellow Israelites who were in poverty. Having to pay back the loan with “usury,” or interest, would only put them further into debt and was not beneficial to the economy. Loans to foreigners, however, were considered international business and approved. This law served as a reminder to the Jews that helping those in need is something that should be done without requiring anything in return.
Most of the loans we know of in modern terms come from banks, and the Bible doesn’t speak much about this. Although the Bible does not explicitly forbid the charging of interest, it does warn against becoming too concerned with money, teaching us that we cannot serve both God and money at the same time (Matthew 6:24). We are cautioned that wanting to be rich leads to despair and that the love of money is the root of all kinds of evil (1 Timothy 6:9-10).
Furthermore, God’s teaching includes a caution not to profit off the desperation of the poor. “Sharks” who extort the impoverished in the time of their distress will not relish their plunder for long: “He that by usury and unjust gain increaseth his substance, he shall gather it for him that will pity the poor” (Proverbs 28:8, KJV).
Usury was condemned by numerous religious leaders and philosophers throughout history, including Moses, Plato, Aristotle, Seneca, Aquinas, Muhammad, and Gautama Buddha.
Certain negative historical renditions of usury carry with them social connotations of perceived "unjust" or "discriminatory" lending practices. The historian Paul Johnson comments:
Most early religious systems in the ancient Near East and the secular codes arising from them did not forbid usury. These societies regarded inanimate matter as alive, like plants, animals and people, and capable of reproducing itself. Hence if you lent 'food money', or monetary tokens of any kind, it was legitimate to charge interest. Food money in the shape of olives, dates, seeds or animals was lent out as early as c. 5000 BC, if not earlier. ...Among the Mesopotamians, Hittites, Phoenicians, and Egyptians, interest was legal and often fixed by the state. But the Hebrew took a different view of the matter.
In 325 A.D., the First Council of Nicaea forbade ministry from practicing usury:
Forasmuch as many enrolled among the Clergy, following covetousness and lust of gain, have forgotten the divine Scripture, which says, "He has not given his money upon usury" [Ezek. xviii, 8], and in lending money ask the hundredth of the sum [as monthly interest], the holy and great Synod thinks it just that if after this decree anyone be found to receive usury, whether he accomplish it by secret transaction or otherwise, as by demanding the whole and one half, or by using any other contrivance whatever for filthy lucre's sake, he shall be deposed from the clergy and his name stricken from the list. (canon 17).
Easton's Bible Dictionary - Usury
Usury - wikipedia.org
Definition of Usury - dictionary.com