It's been a hell of a week for God and for Mammon. "The love of money is the root of all evil" Dr John Sentamu, the Archbishop of York reminded City bankers on Wednesday, adding, rather presciently as it turned out, "We have all worshipped it. No one is guiltless".

Indeed, less than 24 hours after the Archbishops of Canterbury and York had ripped into global capitalism, decrying the greed of "City robbers," it emerged that the investments controlled by the Church itself were involved in short selling – because its stock was lent to enable short selling to happen and because it owned shares in Man Group, a large hedge fund manager. As a morality tale, it was almost worthy of Chaucer’s Pardoner. Radix Malorum est Cupiditas: the Root of all Evil is Money he preaches in The Canterbury Tales, making, in the process, a tidy profit.

Yet for all the justified charges of hypocrisy, this weeks’ battles between Church and City have, if little else, turned the spotlight on God and the question of what, if anything, the world’s main faiths, Islam, Judaism and Christianity have to say about finance, debt and spirituality.

The answer is perhaps most obvious in Islam – specific verses of the Qur’an expressly forbid the charging or paying of interest says Sultan Choudhury, Commercial Director of the Islamic Bank of Britain. “Usury is a very big sin in Islam, one verse in the Qu'ran forbids it and another says that God will declare war on those who undertake it,” he explains.

Islamic banking services are designed to reflect this, he says: “The ban on usury means you cannot make money from money and for legal (as per Shariah) trading a real transaction has to take place."

In practice, what this means is that "a shopkeeper, for instance, is allowed to buy rice and to sell it on to the customer at a profit because a physical trading activity has taken place. What it does not allow is for Adam to give Mary £100 and demand £101 back the following week without a real asset or service being exchanged.”

Furthermore: “Islam also imposes ethical restrictions on what you trade and how you trade. There are detailed rules about transactions. Long before consumer legislation came, Islam said that there must be no deception involved in a transaction, that a transaction must be transparent for the consumer," Choudhury explains. He adds "Another very strong principle is that a transaction has to be linked to a real asset.

" When you look at the credit crunch, you’ve got banks buying paper, which may represent land in Florida, or housing but they are not sure of the underlying real asset. There is a divorce between the monetary system and the real system. By and large, speculation and hedge funds are prohibited in Islam, as is short-selling. You may only sell what you possess," explains Choudhury, drawing a parallel with the recent crisis: "In this case, people are selling things which they have never owned, which is what has been happening with speculators in HBOS. The problems we’ve had are unlikely to happen within an Islamic banking system.”

Usury was once strictly condemned by the Christian Church too: laws enforced during the Lateran Councils of 1215 specified that no one who lent money could enjoy a Christian burial, a ban which virtually forced all money lending to be executed by Jews, who, as a result, have been frequently and unfairly stigmatised for usury, with some websites today even blaming them for the current financial crisis. By the 16th century, despite issuing three papal bulls against usury between 1569 and 1586, the papacy relented, lifting an outright ban on the practice. However, greed, and the charging of exorbitant interest, are still prohibited, says Father Peter Harris, Roman Catholic Chaplain to Canary Wharf. He says Christ used the forgiveness of debt as a frequent metaphor for the forgiveness of sin, explaining: "The essential economy of the Church is debt-free as Jesus has paid the debt. We are the benefactors of God's freely given love through the Cross and Resurrection of Jesus."

The cancellation of debt is also integral to Jewish tradition, says Rabbi Jonathan Romain of Maidenhead Synagogue, who is the Chair of the Assembly of Reform Rabbis UK. “Deuteronomy includes the Jubilee idea of all financial debts being annulled and land sold reverting to the original owners every fifty years. However, this was seen as an ideal rather than a practicality, and there is no record of it happening. Jewish groups have been heavily involved in the Drop the Debt campaigns as a matter of religious principle.”

Unlike Islam, Jews do not attach any spiritual stigma to loaning money with interest, he adds: "It has always been a puzzle to Jews that in some other faiths the idea of wealth is regarded as shameful, while lending money with interest is seen as sinful,” Romain says. He adds “ For Jews, neither are intrinsically wrong, although serious question marks do arise if the method of earning money is dubious or if the interest charged to others is excessive.”

Conversely, there is no objection to Jews receiving credit, which is also seen as a normal mechanism of business and free of any religious strictures. However, it is subject to the caveat that if there is no intention of repaying the debt - or clearly no ability to do so - then taking a loan amounts to stealing and transgresses that commandment."